The Red Sox have had quite the auspicious last few weeks. Their 16-6 record since June 12 is the best in baseball, and they’ve elevated their playoff odds to a season-high 48.0%, an excellent performance for a team that entered the year with a sub-.500 projection. In a tight AL Wild Card race, they’ve needed every single one of these recent victories, as Dan Szymborski recently found that Boston’s playoff hopes are more sensitive to small changes in the standings than those of any other team. As the trade deadline approaches, the Red Sox may find themselves in the running for big names. Much of their current success, though, is thanks to major improvements from players currently on the roster, such as pitchers Tanner Houck and Kutter Crawford and catcher Connor Wong, whom Jay Jaffe wrote about yesterday. And no Red Sox player has leveled up his game more than the current team leader in plate appearances, runs scored, and WAR: Jarren Duran.

Duran’s breakout has come during his first season of full-time play; after cups of coffee in 2021 and ’22, he served as the strong side of a platoon last season, amassing a 120 wRC+ across 362 plate appearances. But there were some signs of future regression, as he outperformed his xwOBA by 35 points and relied on a .381 BABIP to slash .295/.346/.482. And while those raw numbers from 2023 have actually declined this season, to .275/.337/.473, Duran has put up a nearly identical 121 wRC+. Most encouragingly, he has much stronger peripherals backing up his slash line this year, indicating that his current production is sustainable.

The biggest change we’ve seen from Duran in 2024 is in his approach at the plate. Previously, it seemed as though his goal was to swing at anything near the strike zone and put the ball in play; he offered at the first pitch nearly 40% of the time. And while this strategy worked for him because he made a lot of contact, frequently on a line, his success depended on well-placed balls in play and didn’t make the most of his strength. Instead, it often felt like he sacrificed damage for contact, an unnecessary tradeoff given his solid bat-to-ball skills, especially on pitches in the strike zone. His power numbers last year – a 20th percentile barrel rate and 35th percentile xSLG – were far from what he was capable of.

Although Duran doesn’t look like the most physically imposing player on the field, he has excellent raw power, with maximum exit velocities over 112.5 mph in each of the past two seasons. He’s especially lethal against pitches down and in, where his bat speed, exit velocity, and overall production are all elite. Comparatively, he’s generated negative run values against pitches on the outer third or top of the zone, as his relatively long swing isn’t able to cover the needed distance in time. Understanding this, Duran has become more selective. He’s cut his first-pitch swing rate nearly in half, watching such offerings go by at nearly Mike Trout levels. He’s dropped his swing rate on strikes in his cold zones by nine points, in addition to a reduction in chase rate. The results of these adjustments has been staggering, and Duran has looked like a brand new hitter this year. Even without an increase in raw strength, Duran’s focus on swinging only at the best pitches have vaulted his barrel rate above the league average, along with his xSLG and xwOBA. Additionally, his taking more called strikes has aided more than just his power numbers: His strikeout and walk rates have actually improved with his new approach.

Remarkably, Duran legged out 34 doubles last year, 10 more two-baggers than he’s hit across 50 more trips to the plate this season. As we know, as many young players gain more experience, they learn how to turn those two-base hits into home runs — or as Kiri Oler dubbed this development, “summiting Doubles to Dingers Mountain” — so it’s not all that surprising that Duran is hitting fewer doubles as he’s added power. Except, well, he’s launching home runs at nearly the same pace as he did last year, in 2.4% of his plate appearances this season, up slightly from 2.2%. Instead, he’s managed to one-up his power production in a far less common way: He’s hitting way more triples. He’s still racking up plenty of doubles (24, tied for the fifth most in baseball), but he leads the majors with 10 triples, eight more than he hit last season. Altogether, he ranks fifth in the majors with 44 extra-base hits. He’s taking full advantage of the dimensions of his home stadium, as Fenway’s deep right-center field gap and the Green Monster in left make it the most doubles-friendly ballpark in the majors, especially for left-handed hitters, and the fifth-most triples-friendly park. This season, Duran has 18 doubles in just 133 balls in play at home. More specifically, Duran’s ability to smack balls off the Monster is absolutely unparalleled. I looked at spray charts of other prolific Red Sox hitters in recent memory – Rafael Devers, Xander Bogaerts, Mookie Betts – and none took advantage of their ballpark’s defining feature anywhere close to as frequently as Duran has in 2024.

Many of Duran’s 34 combined doubles and triples this year have resulted from his speed on the basepaths, fighting to take the extra bag at every opportunity. He’s always possessed plus-plus speed, and using Statcast’s new baserunning value leaderboard, we can see the run value of every single he’s stretched into a hustle double or base taken on a teammate’s hit. Duran ranks third in the league in such runs generated thanks to his aggression, and while a handful of speedsters have produced negative value from being overly cautious, Duran’s fearlessness has paid off. Aggressive baserunning has been an important part of Boston’s overall offensive improvements this year. The Red Sox have climbed to seventh in extra base taken rate compared to 25th a year ago. Statcast views them as the fourth-best baserunning team in baseball. When you combine this with Duran’s 21 steals on 24 attempts, the end result is one of the most valuable runners in the league; besides Duran, only Corbin Carroll and Elly De La Cruz are on pace to accrue 1 WAR from baserunning alone.

While Duran has solidified his approach at the plate and maintained his excellence on the basepaths, the area where he’s seen the most dramatic improvement this year is with his glove. Despite his 95th percentile sprint speed, Duran’s previous performance in the outfield, especially in center, left much to be desired; he totaled -5 FRV from 2021-23. Most of his poor plays occurred when he had to cover long distances on efficient routes; it was so bad that he made an appearance in a piece I wrote last year due to his awful route running. In that piece, I found there was a negative correlation between route efficiency and overall OAA, as an outfielder’s initial reaction and burst speed proved to be more important factors. Duran has been a key example of this: His routes are still rough, but the rest of his defensive game has improved tremendously. His +5 FRV ranks in the 89th percentile (though second to Ceddanne Rafaela in his own outfield), while only Daulton Varsho has more DRS than Duran’s 12 among outfielders.

Duran’s reactions and first steps have improved to the point where his routes haven’t impacted his ability to get to balls. Last year, he failed to make both of the difficult-but-possible plays that involved covering over 100 feet of ground to make the catch; this year he���s a perfect 4-for-4. However, the plays that have turned his defensive metrics from below average to excellent aren’t the long-distance runs but the line drives, where instincts and initial reactions are everything. In 2024, Duran has had 11 play opportunities on balls between 30 and 50 feet away from him with fewer than four seconds to make the catch. He’s converted 10 of them, contributing to half of his total OAA. While he was similarly successful at catching these hard liners in previous seasons, he had only a few such play opportunities. Duran isn’t doing anything different with his positioning this year, so it remains to be seen whether he’ll continue to get so many catch opportunities on these hard liners. Regardless, it’s safe to say that he’s made the most of the fielding chances he’s been given.

Nearing the All-Star break, the Red Sox have as close to coin-flip playoff odds as any other club, and the high stakes they’ve played under combined with their meteoric performance over the past few weeks have made them one of the most exciting teams in baseball to watch. And in the middle of it is the homegrown All-Star Duran, whose improvements have manifested in every single aspect of his game.

The Angels are in a rough place. With Mike Trout injured, Shohei Ohtani departed, and pitchers like Patrick Sandoval and Reid Detmers injured or struggling, it’s no surprise that they’re on pace for another 90-loss season despite a recent six-game winning streak. Their main source of their woes has been their long-struggling pitching staff, which this year has the third-worst ERA and walk rate in the majors. And while the Angels have taken extreme measures to add pitching depth to their farm system, the next generation of young pitchers in Anaheim aren’t exactly aces. This is to say that any short-term improvements to the staff will have to come from improvements to hurlers already on the big league roster. This year, they’re attempting to do just that by embracing the newest pitch to come into vogue: the splinker.

The splinker is still pretty new in the timeline of pitch design; its early adopters include Jhoan Duran and Paul Skenes. This sinker-splitter hybrid is difficult to classify because so few pitchers throw it, but such offerings generally sit in the same velocity band as four-seam fastballs while killing spin and lift in a manner similar to splitters and changeups. The end result can be downright nasty: Skenes has accumulated a +10 run value with his splinker across just nine starts, only a couple runs better than the first Angel to pick up the pitch, José Soriano. Read the rest of this entry »

This has not been the year for the AL West. With the reigning World Series champion Rangers sitting below .500 amid a string of injuries, the Astros’ core succumbing to age, and the Angels and A’s sitting at rock bottom, one of baseball’s stronger divisions over the past few years has become its weakest. Just one team has a winning record: the Seattle Mariners. At 43-31, the Mariners hold an 8.5-game lead in the West, even as some of the underlying numbers indicate the team isn’t as good as its record suggests. Seattle has overperformed its Pythagorean record by four wins and its BaseRuns record by two, and its run differential is by far the worst among division leaders. But this kind of thing is nothing new for this organization.

The Mariners are currently enjoying their fourth consecutive year of contention, falling short of a Wild Card spot in 2021 and ’23 and snapping their two-decade playoff drought in ’22. In each of these seasons, they’ve pulled out wins in close games like no other club, and manager Scott Servais has pointed to the poise and experience with which his team handles tight matchups. Famously, after a 2021 road trip where the Mariners went 6-2 despite being outscored by their opponents, Servais introduced the term “fun differential” to evaluate the team rather than its relatively poor run differential. Three years later, with a new group of players, the fun differential is still elite.

Naturally, in order to win a lot of one-run games, you need to play in a lot of one-run games. One of the best ways to do that is to play plenty of low-scoring affairs, when neither team scores enough runs to pull away from its opponent. And indeed, the Mariners rank in the bottom third of the majors in both runs scored and allowed. The first factor that puts them in so many tight games is the strength of their starting rotation, which has been among the best in baseball by both volume and efficiency. As a squad, they rank eighth in ERA- and FIP-, and second in innings per start; they’re one of just two teams to convert quality starts over half the time. While none of their starters are individually dominating the leaderboards, the depth they have is nearly unmatched. The Mariners are one of three teams (along with the Phillies and Yankees) with four qualified starters with an ERA- of 95 or lower, and even Seattle’s fifth slot (with starts made by Emerson Hancock, Bryan Woo, and Jhonathan Diaz) has pitched to a 3.25 ERA. In short, they’re the only team in the league that can expect to have good starting pitching every single night.

On the flip side, Seattle’s offense has taken a significant hit from last year. Lineup mainstays like J.P. Crawford, Julio Rodríguez, and Cal Raleigh have regressed this season, though Rodríguez has turned things around over the past month. Many of the hitters Seattle added during the offseason have underperformed as well. Returning fan favorite Mitch Haniger has been below replacement level, and Jorge Polanco and Mitch Garver are each hitting below the Mendoza line.

With an excellent rotation and below-average hitting, the Mariners have the recipe for low-scoring games, but there’s another factor here as well: their home field. T-Mobile Park has been regarded as a pitcher’s paradise since its opening 25 years ago, but it’s been even more unfavorable for hitters in 2024 than in previous years. Statcast’s single-season park factors view it as, by far, this season’s most pitcher-friendly park, with a factor of 87; it has had scores between 92 and 96 for the past half-decade. The end result is that nearly a third of Mariners games have been decided by a single run, one of the highest marks in the league.

Playing in a lot of one-run games is one thing, but winning them is another. The Cubs and Athletics, the only teams with more one-run contests, each have losing records in such games. But the Mariners combine quantity with quality, having the most one-run wins while placing second to the Rays in one-run winning percentage. In contests decided by multiple runs, the Mariners are 26-24 — their .520 win percentage in such games is shockingly close to their .527 Pythagorean record — but one-run wins have vaulted them to a dozen games above .500. Some of these wins have come in dramatic fashion, as their five walk-offs are tied for the league lead. The Mariners have been far from an offensive powerhouse, but all year the bats have come alive when it matters most.

These splits are staggering. In low leverage, the Mariners are one of worst-hitting teams in the league. But when the stakes are highest, they collectively produce like a top-15 hitter in baseball. However, the eye-popping 144 wRC+ figure in high-leverage spots comes with a .377 BABIP – more than 40 points higher than any other team in that split. Come year’s end, that number will certainly be lower than it is now, but looking underneath the hood, Seattle batsmen have still been hitting better in high leverage than low leverage. Their walk rate is three points higher and strikeout rate three points lower in such situations, and their hard-hit rate is also modestly higher.

While Mariners hitters might not be able to forever continue their dominance in dramatic moments, the production they are getting from their bullpen, the other component of their success in one-run games, is far more sustainable. Despite some confusing trades, strong relief pitching has been a strength of recent Seattle squads. The organization has a knack for finding, acquiring, and developing under-the-radar relievers.

Andrés Muñoz is enjoying his first full season as Mariners closer, but he hasn’t been deployed solely in ninth-inning save situations. In fact, only half of his appearances have begun at the start of the ninth inning. He’s been called upon for a couple of extra-inning appearances, but his most notable work has come when he’s inherited a dirty eighth inning and converted a four- or five-out save. Muñoz has recorded more than three outs in seven games, second to Mason Miller among full-time closers, and in those games, he hasn’t surrendered a single run. Servais has consistently picked the right time to get his relief ace onto the mound, as Muñoz has the highest average entrance leverage index in the league.

Veteran reliever Ryne Stanek and 31-year old breakout Tayler Saucedo, who each rank above some closers on the leverage index leaderboard, have mostly handled set-up duties ahead of Muñoz. The two of them complement each other well, as both Stanek, a righty, and Saucedo, a lefty, have significant platoon splits, and Servais shrewdly deploys them based on matchups.

Among Seattle’s lower-leverage options, former starters Austin Voth and Trent Thornton have hit their stride coming out of the bullpen; the pair lead the staff in relief innings while effectively keeping runs off the board.

It would be easy to chalk all of this up to luck, even within the context of the other recent Mariners teams. Their offense has less thump than it has in previous years, and their bullpen is more reliant on high-leverage studs than an entire stable of them. Yet, they still have the ingredients that have made them so successful in tight games, even if the recipe is a bit different. Besides, maybe a slight variation is a good thing. After all, in recent years the best the Mariners could do was secure one AL Wild Card berth. Now, for the first time in their fun differential era, they are in position to ride their recipe for success all the way to a division crown.

Baseball is a game all about decisions. Some are minuscule, micro-level decisions that everyone will forget about after they happen. Should I sit fastball on this pitch? Should I take off for second base? Meanwhile, some are much larger, macro-level decisions felt over the course of one or multiple seasons. Should I try to lift the ball more? Should I change the grip of my slider? Everyday games over the course of a long season let us keep track of these larger trends, but no one could possibly analyze every substitution or pitching change over a 2,430-game regular season. So, instead, I’ll look at just three. In a midweek series last week, the Phillies and Giants put on a clinic of cat-and-mouse strategy and mostly excellent pitching. Let’s take a look at both the small- and large-scale decisions that contributed to this excellence on the mound.

Game 1 was a relatively high-scoring affair in which neither starter shined. There was nothing interesting to report from the Phillies side, as backend starter Taijuan Walker completed six innings but allowed as many runs. Opposite him was the struggling Blake Snell, who, in his typical inefficient fashion, lasted just four innings before being removed. To begin the fifth, manager Bob Melvin turned to rookie Randy Rodríguez, a sensible choice given his consistent multi-inning appearances to provide length to the Giants bullpen. In his first inning, Rodríguez retired the heart of the lineup in order on just 10 pitches, making him the easy choice to come back out for the sixth, due to face a pair of Phillies platoon hitters inserted into the lineup to face Snell.

Pache and Merrifield really aren’t guys you want hitting against a righty, especially one as nasty as Rodríguez, whose absolute hammer of a slider creates a difficult look for same-handed batters. Despite Marsh and Stott, the regular starters, ready to pinch-hit, Phillies manager Rob Thomson elected to keep them on the bench in a one-run game. His reason was the man standing on a bullpen mound beyond the center field fence: Lefty Erik Miller was warming up for the Giants.

While the Giants could have sent in Miller in response to a pinch-hitter, I still think using Marsh and Stott would’ve been the correct decision for Thomson. First, given Pache and Merrifield’s futility against right-handed pitching, almost any other scenario would have been more favorable. Indeed, the two managed a fly out and groundout against Rodríguez, combining for an xBA of .090. Furthermore, with lefty sluggers Kyle Schwarber and Bryce Harper at the top of the lineup (with a 91 and 72 point gap in projected OPS, respectively, between their splits vs. right-handed and left-handed pitchers), it would’ve been wise for Thomson to force Melvin to burn one of the two lefty relievers in the Giants bullpen, which could’ve led to more favorable matchups later in the game. Because Thomson decided not to make any substitutions, Miller wasn’t needed until the next inning, a scoreless effort in which he allowed just one hit, the popup single in front of home plate that Ben Clemens wrote about in Friday’s Five Things column. Marsh and Stott did eventually hit in the ninth, as did lefty bench bat Kody Clemens, but only after Philadelphia’s deficit had ballooned to four runs.

The fact that Miller only threw one inning in Game 1 became significant the next day, as he was fresh enough to slot in as the opener for bulk man Spencer Howard, a former Phillies top prospect who stalled upon hitting the majors and entered play with a career ERA north of seven. Thomson rolled out the lefty-heavy lineup hoping to feast on Howard’s mediocre fastball shape, so for the second day in a row, Miller faced the Phillies’ top three without allowing any damage. In traditional opener games, Howard would come out next and make his start as normal. Instead, Melvin went a different route, delaying Howard’s entrance in favor of bringing in Taylor Rogers, the only other available lefty he had. It’s not the first time a team has used multiple openers, but it’s certainly unorthodox during the regular season, with few off-days to rest the staff. The left-handed Rogers twin breezed through two scoreless innings, turning the lineup over before handing the ball off. Howard still had to get the job done, but Miller and Rogers lessened his load by nine outs, taking out a lefty-vulnerable lineup that wouldn’t turn to pinch-hitters so early in the game. Howard turned in four scoreless frames, and his team needed every bit of it, as they won 1-0 in extras.

Melvin’s management of his staff made the most of his available, although depleted, personnel. Under ideal circumstances, teams wouldn’t use emergency bulk arms, multiple openers, or an entire staff composed of swingmen, but an open rotation spot due to injury forced the Giants to scrap together innings by any means necessary. While Melvin’s tactical decisions were the best use of his limited arms, the opposite side of this matchup showed a fully operational, elite rotation at its finest. The Phillies currently have the best starting pitching in the league by every measure, and it’s not particularly close.

Most of that value comes from four excellent arms, two of which appeared in this series. First, in the second game, it was Zack Wheeler, who has continued his run as baseball’s most consistently excellent starter over the past half-decade. Even with his velocity finally starting to show signs of age, he’s on pace for career bests in ERA (2.32) and xERA (2.60), and his 29.0% strikeout rate is just below the career-high 29.1% mark he posted in 2021. Much of his success has come from an eagerness to change his approach and arsenal over time – first emerging as a Cy Young finalist after embracing the power of the elevated fastball, then adding a new pitch to his arsenal in each of the last two seasons. In 2023, a sweeper became his breaking pitch of choice; this season, like many other pitchers, he’s added a splitter. Wheeler now throws six pitches with regularity, a re-invention of his style from just a few years ago.

In dominating the Giants, Wheeler demonstrated the complementary power of his sinker and new split, with the former earning called strikes at a 29% clip and the latter inducing four whiffs on just 10 uses. The splitter has above-average run just like his two-seamer; it even spins on the same axis after adjusting for seam-shifted wake. It’s almost as if Wheeler precision engineered his splitter to travel on the exact same tunnel as his sinker for the first 40 feet of flight before diverging, making it extremely difficult for batters to tell them apart. The brand-new splitter is already Wheeler’s best secondary offering by run value, and it’s also helped make his sinker considerably more effective, with a 40-point drop in xwOBA compared to last season.

Wheeler put together one of his best starts of the season, striking out nine San Francisco hitters across six scoreless innings, but he couldn’t outdo his opponent’s parade of openers and was saddled with a no-decision. The next afternoon, in the series finale, Cristopher Sánchez enjoyed a Phillies offensive outburst that was absent from the first two games. In last year’s breakout campaign, the lefty Sánchez put up above-average numbers over 19 appearances, but what held him back from excellence was an abysmal showing against right-handed hitters, who ran a slugging percentage that was more than double their that left-handed counterparts. He’s leveled up this year, currently holding a share of the NL lead in FIP. And while he still runs an exaggerated platoon split, he’s been able to limit the power of opposite-handed hitters, as seen on Wednesday against a daunting all-righty Giants lineup.

The calling card of Sánchez’s arsenal is a changeup with few comps in terms of movement, boasting 97th percentile drop and 95th percentile run. This exceptional pitch generated gaudy whiff numbers during his time as a prospect, and has only continued in the big leagues. The problem is that Sánchez’s sinker, which he uses to set up the changeup, gets absolutely hammered, especially by righties. Drastically cutting his sinker usage wouldn’t be the solution, because that would allow batters to sit on his change and make it more hittable. So, rather than shelving the sinker, Sánchez made a change to when he used it.

Sánchez took advantage of the Giants’ passivity on first pitches by throwing juicy sinkers to 12 of the 24 batters he faced; none of them were put into play. In fact, over a third of his sinkers in the game were taken for called strikes, his highest mark of the season. After getting ahead in the count, Sánchez then let the changeups rain down, racking up strikeouts and groundouts. By the end of the start, Sánchez’s sinker — a pitch that had allowed loud contact like no other in the past — surrendered zero barrels and zero extra-base hits. Like Wheeler the day prior, Sánchez turned in six scoreless innings, while the Philadelphia bats knocked around the surprisingly hittable Kyle Harrison. The vulnerability of Sánchez’s sinker likely caps his upside as a mid-rotation guy, but certainly one more than capable of starting playoff games for his contending team.

The Giants won the series, taking two games out of three. They showed they could win even with a starting rotation depleted by injury and underperformance, tilting the odds in their favor with crafty personnel decisions that kept the Phillies’ offense guessing as to who would come out next. (Of course, over the weekend, the Giants were swept by the Yankees in San Francisco, perhaps displaying the limitations of a team with a shaky staff.) On the other side, Philadelphia’s buzzsaw of a rotation was created by decisions as well, albeit ones made on the more macro level. From arsenal tweaks to command improvements, these changes demonstrate why this team is top dog right now in the National League.

This is the year of the splitter. In 2024, 3.1% of all big league pitches thrown have been splitters compared to 2.2% in 2023, a year-over-year increase of 41%. Aficionados of the split-fingered fastball include former NPB stars like Yoshinobu Yamamoto and Shota Imanaga, longtime MLB users like Joe Ryan and Fernando Cruz, and an assorted collection of hurlers who’ve added a new splitter or featured one much more prominently in their arsenal this year. And few starters have scaled up their splitter usage more than the man atop the pitcher WAR leaderboard: Tanner Houck.

Houck has thrown a splitter his entire time in the majors, but he’s taken it to a new level this year by doubling its usage. Among qualified starters, Houck throws the sixth-highest percentage of splitters, while his splitter’s 110 Pitching+ ranks fifth, ahead of Ryan and Imanaga. The rise of Houck’s splitter, combined with the arsenal tweaks he’s made to throw it more, have transformed him from a mixed-role swingman to slam-dunk frontline starter.

Houck has spent most of his big league career straddling the line between starter and reliever. He pitched mainly as a starter during his 2021 rookie season, but never completed the sixth inning in any of his starts. His sophomore campaign saw him make multi-inning appearances out of the bullpen. Back in the rotation last year, he posted an ERA above five and struggled to get outs as his pitches lost their bite later in starts.

Aside from stamina, Houck’s delivery served as a hurdle to his abilities as a starter. While a handful of starters fire from low arm slots, Houck is one of the only true sidearmers currently in a big league rotation. He doesn’t have an outlier release point thanks to his tall stature and mechanics that carry him toward the first base side, but his arm angle is certainly the lowest among starters. Houck’s delivery provides a great viewing angle for left-handed hitters, who comprise the majority of his competition as opponents stack platoon bats against him.

In 2023, lefties slashed .271/.356/.502 against Houck, roughly the equivalent of having to face Rafael Devers for the entire season. But through his first 10 starts of this year, he’s held them to a line so poor I can’t find a qualified hitter whose numbers I can compare with it. Neutralizing the platoon advantage is a huge deal for a pitcher with his arm angle, and much of this impressive feat has to do with his splitter.

Let’s take a look at what Houck’s approach to pitching looked like before ramping up the use of his splitter. Like most low-slot pitchers, his two primary offerings are a sinker and slider, taking advantage of the east-west movement his arm action produces. Both these pitches are chart-topping in terms of movement, dropping more than average due to their lack of backspin, and his slider breaks to the left even more than most sweepers (though Statcast doesn’t classify it as one).

While these two pitches made right-handed hitters absolutely futile against Houck, sinkers and sweeping sliders tend to generate large platoon splits, compounding with the advantage lefties gain from seeing the ball clearly out of his hand. Houck’s slider drops so much that lefties can’t do much with it, but his sinker moves directly into the path of their barrels, eager to get hammered. In the past, Houck primarily used four-seamers and cutters as his hard offerings against lefty opponents, hoping the rising action would be enough to miss bats. But these pitches still had too much arm-side movement and didn’t generate upward Magnus force, instead staying on plane with lefty swings.

Houck’s approach to lefties wasn’t working, and he needed a change. In came the splitter. What was once a distant fourth offering became his offspeed weapon. He tinkered with its shape, adding nearly four inches of drop to make it more distinct from his sinker. He tightened up its command, finishing down in the zone more consistently and spiking fewer in the dirt. The end result of these adjustments is a lethal pitch that has been a key contributor to Houck’s success.

Houck’s splitter leads his arsenal in both swinging strike rate and putaway rate, indicating it’s already his go-to weapon in two-strike counts. And while it’s been successful at missing bats, the results it generates when batters put it in play may be even more impressive. His split has the lowest launch angle allowed of any individual pitch from a starter; it’s one of just a dozen with a negative average launch angle. After years of allowing lefties to crush the ball in the air, he’s inducing a higher groundball rate against lefties than righties in 2024. These underlying changes have manifested in big time results – lefties have just a .038 ISO against Houck this season and have yet to homer, and Statcast metrics like barrel rate confirm this is no fluke.

The emergence of Houck’s splitter has also cut down his walk rate significantly, as he’s jumped from the 42nd to the 88th percentile in avoiding free passes. Previously, Houck often nibbled around the zone against lefties, afraid of what they could do to his fastball and cutter. Now armed with a pitch that limits damage, he’s fearlessly attacking the strike zone, improving his splitter zone rate by 14 percentage points and his overall zone rate by nearly five.

The effectiveness of his splitter has also made Houck’s sinker a more effective strike stealer because hitters watch it go by expecting it to drop beneath the zone. Houck currently ranks second to Seth Lugo in called strike rate, getting ahead of hitters before disposing of them with the slider and splitter. His improved control of the count is a big reason why he ranks fourth in K-BB% increase relative to 2023.

What impresses me most about Houck’s splitter is the sheer frequency with which he deploys it against lefties, especially at the expense of his fastballs. He’s throwing significantly fewer cutters and has shelved the four-seamer entirely. After unsuccessfully throwing the kitchen sink against opposite-handed opponents, he’s essentially become a two-pitch pitcher against lefties, throwing either a slider or splitter nearly three-quarters of the time.

It’s not often that you see a pitcher use two different non-fastballs as their primary offerings, but this strategy has paid off – not just for Houck but also for the Red Sox as a whole. Last month, Chris Gilligan wrote about Boston’s staff leading the leaguewide shift away from the fastball, pointing out Houck’s four-seamer had a horizontal movement profile ripe for hitters to feast on. Just a couple decades ago, a starting pitcher who almost exclusively relied on sliders and splitters against left-handed hitters would have been unthinkable, but the secondaries-first approach is now a strategy that entire teams are embracing with tremendous results.

Houck’s run as the top-performing pitcher in the majors probably won’t last — he has an unsustainably low 2.6% HR/FB rate — but the excellence of his splitter has certainly put a massive up arrow on his future projection. Just a couple years ago, it would’ve been difficult to envision that the sidewinding swingman who couldn’t handle lefties would become an excellent starter who consistently works into the seventh inning. But with a surprisingly simple fix, Houck has made it happen.

Less than a year after being drafted first overall, Paul Skenes made his first major league start for the Pirates. On Saturday, nearly 35,000 fans packed the stands at PNC Park in Pittsburgh for the occasion, hoping to get the first glimpse of a new era for the long-struggling home team. It was impossible not to draw comparisons to Stephen Strasburg’s debut in 2010, a masterpiece in which he struck out 14 batters, coincidentally against the Pirates. Perhaps no pitching prospect in history has come with the same hype that Strasburg did as he ascended through the minors, but the buzz surrounding Skenes comes close. Let’s see how he began his big league career.

Even those who haven’t read the full scouting report on Skenes know that he throws incredibly hard, and he needed just one pitch to associate himself with triple-digit Trackman readings. While he’s averaged 99 mph during his (mostly abbreviated) minor league starts over the past month, Skenes opened up the game with 101 mph heat and sat at 100 throughout the start. He threw mostly fastballs to leadoff hitter Mike Tauchman, save for a slider that missed outside. After reaching full count, Skenes collected his first strikeout in style.

Prior to Saturday, no starting pitcher in 2024 had thrown a pitch at 101 or higher. Skenes did so six times before his debut was over. While velocity might be the best known part of his game, Skenes has developed a deep arsenal of pitches, the newest of which he put to work against the next batter, Seiya Suzuki.

This splitter-sinker hybrid, or “splinker,” is a pitch with few comparisons; only Jhoan Duran and José Soriano throw any offering remotely similar. It feels impossible to throw in the mid-90s while simultaneously killing enough spin to give the pitch a negative induced vertical break, but Skenes rips these off with ease. He tends to use this pitch as more of a sinker than an offspeed offering (after all, it averages 95 mph), deploying it mostly against right-handed hitters while saving his lesser-used, upper-80s changeup for lefties. Suzuki could only watch the splinker go by. He couldn’t do much more with the next two pitches he saw, either. Let’s play them back to back.

First, Skenes claimed strike two with the harder version of his slider. After seeing something that broke a foot toward him, Suzuki flinched a bit at a that pitch, which ended up solidly in the zone. Well ahead in the count now, Skenes went in for the kill. This sweeping slider was his most-used pitch against righties in his start, featuring 15 inches of gloveside break. Moreover, because Skenes releases the ball so far on the third base side of the mound, it approaches the plate at a more extreme angle and makes it even more difficult to hit. All Suzuki could do was flail at it for strike three.

Skenes finished his first three innings of work without allowing any runs, though he issued two walks and hit a batter. At times, he struggled to find his release, finishing late with the fastball and ending up with a clump of misses below the zone to the gloveside. He also threw a sizable number down the heart of the plate, and Cubs hitters squared up a trio of them. With his slider, he would sometimes release early and cause the pitch to back up over the plate, but the few that he landed on the outside corner, mainly of the sweeper variation, were among his best pitches of the day.

While Skenes certainly has room to grow with his fastball and slider command, he threw his splinker with remarkable accuracy and consistency throughout his start. With the exception of the pitch that hit Nico Hoerner, Skenes’ splinkers lived at the bottom of the zone or right below it; that’s especially impressive considering he’s been throwing that pitch for only a couple months. Spotting it on the edges of the zone makes it so challenging for hitters to decide whether to swing, let alone make contact if they do. The pitch led Skenes’ arsenal with a 55% chase rate, 53% CSW, and seven swinging strikes, including these two to Ian Happ to start the fourth inning.

After dispatching Happ with a fastball, Hoerner stepped up for his second plate appearance. He quickly exacted his revenge for the second-inning plunk, pulling a first-pitch slider left over the middle for a home run that barely cleared the left field fence. Many gyro sliders feature late downward break, but unlike those thrown by the likes of Jeff Hoffman and Dylan Cease, Skenes’ has a few inches of rise compared to a ball thrown without spin. Without the downward bite, batters have an easier time barreling it up when he doesn’t locate it well. That’s what happened with the slider to Hoerner, who easily kept his swing on its plane and hooked the pitch out of the yard because it didn’t dive low and away from him. In his report, Eric Longenhagen explained that Skenes’ low arm slot is a likely cause of this pitch shape, as Skenes tends to get around the side of the ball instead of imparting motion on the vertical axis.

Skenes recovered nicely from the blemish on his line, fanning two more Cubs to put his total at seven through four innings. He had thrown 74 pitches, one shy of his season high in Triple-A. Had his day ended here, I think most would have been satisfied with what they saw – a dominant yet imperfect performance that gave a rosy glimpse into the future. But his start wasn’t over yet.

Much of what I’ve written about here explains why things happened. Skenes overwhelmed hitters with his fastball because he threw it so hard. He had success with his splinker because he located it so well. He gave up a homer with his slider because he hung it up in the zone. But I have no rational explanation for what happened next. Skenes, on a short leash, was pulled quickly after ground balls from Tauchman and Suzuki found just the right holes to end up as hits. Kyle Nicolas entered the game in relief, quickly striking out the next two batters before hitting the third. With two outs and the bases loaded, he proceeded to throw 12 consecutive balls, allowing a trio of runs to score, two of which were charged to Skenes. But even as Nicolas was removed from the game, the inning was far from over. Josh Fleming and Colin Holderman combined to walk in three more runs before the inning’s merciful conclusion, which took nearly three hours thanks to a rain delay.

Skenes, in a rather unfortunate feat, tripled his ERA while sitting on the bench. But he certainly gave a lot to be excited about while on the mound. Despite having just 34 minor league innings under his belt, he is certainly a different pitcher than he was this time last year at LSU. Most notably, he has expanded and diversified his arsenal considerably, and while some wondered whether he would have a viable third pitch in the majors, he showed off a six-pitch arsenal in his first career game.

We still talk about Strasburg’s debut 14 years after it happened, not only because of the incredible results but because of what he meant for the future of the Nationals franchise. Soon after, Strasburg was joined by other homegrown talents like Bryce Harper and Anthony Rendon, and much later, Juan Soto. Washington won a World Series after a decade of contention, and Strasburg was the series MVP. What Skenes brings to Pittsburgh is no different, with his call-up carrying the optimism that he would be one of a new wave of young talents who’d come to reverse the fortunes of a team and city. Skenes didn’t have the legendary debut performance that Strasburg did, but he certainly pitched well enough to keep that hope alive.

Among the crowd of high-end starting pitchers to sign with new teams over the offseason, perhaps none had wider error bars surrounding his projection than Shota Imanaga. An NPB star for the past half-decade, Imanaga had a track record of success but also many questions about how his skills would translate to MLB. This certainly is reflected in his contract with the Cubs, which came with just two guaranteed years worth $23 million, a far cry from our $88 million estimate. But for the past month and change, the 30-year old rookie has been up there with the league’s best.

Through his first seven starts, Imanaga has allowed just five earned runs, fewest among qualified pitchers. He’s been downright dominant through much of this stretch, proving his stuff is up to major league standards while controlling the strike zone better than almost anyone else. But he’s done so differently than other top pitching talents. Let’s take a look at his pitch arsenal.

From a quick glance at the stat sheet, the first thing that catches my eye is the sheer frequency with which Imanaga uses his fastball. In an era where nearly two-thirds of starters throw non-fastballs a majority of the time, Imanaga’s 58.4% usage (91st percentile) stands out. As pointed out by MLB.com’s David Adler, Imanaga’s heater has been the best individual pitch in baseball by run value, beating out Corbin Burnes’ notorious cutter Tyler Glasnow’s frightening fastball. But while the other heaters at the top of this list sit in the mid- to upper-90s, Imanaga’s four-seamer averages just 92 mph.

The list of starters who sit at 92 or below is rather short, and mostly consists of names that we certainly don’t think of as strikeout artists. In his piece, Adler noted that Imanaga’s fastball has elite induced vertical break (IVB). But carry alone doesn’t always make a fastball effective; Triston McKenzie’s four-seamer, which currently leads the league in fastball IVB, has the highest xwOBA allowed of any such pitch (min. 50 plate appearances). Rather, what makes Imanaga’s offering so special is its plus movement in combination with its ultra-low release point.

Pitchers like McKenzie and Ross Stripling throw from high, over-the-top arm slots, making their backspin (and thus vertical movement) predictable for hitters. In contrast, Imanaga’s delivery from a low three-quarters slot creates a movement profile much different than what you’d expect from his arm angle. Earlier this week, Michael Rosen broke down the biomechanics of Imanaga’s ability to spin the ball so well from an outlier release point, showing how his hip and lower-body flexibility enable him to “get behind” the ball and create backspin. Throughout the league, no starter gets a higher IVB than Imanaga does from such a low release point – those throwing from lower slots are primarily sidearmers whose deliveries generate run at the expense of carry, while the only two hurlers with more IVB (min. 250 four-seamers), McKenzie and Tyler Anderson, have release points about a foot higher.

Because of its low release point and high carry, Imanaga’s four-seamer has the third-shallowest vertical approach angle in baseball, creating the deception that causes batters to swing under it with surprising frequency. Its 12.5% swinging strike rate and 22.1% putaway rate easily exceed the league averages of 10.3% and 17.9%, respectively, as he’s able to throw it for a whiff in any count.

Imanaga gets more fastball whiffs than most, but his swinging strike rate with the pitch is a far cry from Jared Jones’ league-leading 20.1%. To be the most valuable pitch in baseball, Imanaga’s fastball has to work even when he’s not blowing it past hitters. And at first glance, you might think that a low-90s heater that lives in the zone would get sent a long way when batters connect with it. Indeed, homers were the one knock on Imanaga’s game in NPB, as his 2.9% homer rate (1.04 HR/9) last year was highest in the league in a deadened offensive environment. But he’s allowed just three homers across his seven MLB starts, and the Statcast data indicate this low total is more a product of skill than luck.

I’m not saying that a 0.65 HR/9 represents Imanaga’s true talent (ZiPS forecasts a 0.94 mark for the rest of the year), and it’s certainly likely that the results will regress toward his xwOBA as the season goes on, but he’s clearly been keeping pitches away from barrels at an above-average clip, a skill that many evaluators were skeptical of as he made the leap to MLB. Part of this is due to his fastball’s shape – a flat VAA can lead to uncomfortable swings and produce weak outs. While this type of fastball does contribute to a high fly ball rate, opponents haven’t been able to put a charge into their aerial hits thus far. Imanaga’s average exit velocity and hard-hit rates allowed sit around the league average, but his exit velocity allowed on batted balls in the air is a much more favorable 70th percentile. He also has the ninth-lowest line drive rate among qualified starters, almost never allowing squared-up contact.

Imanaga also locates his fastball in places unlikely to produce barrels. Sure, he throws more heaters in the zone than almost anyone else, but he’s not just sending them down Broadway and hoping for the best; instead, he’s consistently hitting his spots at the top edge of the zone. He ranks 10th in fastballs thrown in the upper third of the zone, an area where the flatness of the pitch can play up and create the illusion that it’s rising. Unsurprisingly, his Kirby Index, a stat that measures release angle consistency, ranks in the 90th percentile.

Imanaga’s fastball alone has made him one of the most effective pitchers in the league, and I haven’t even talked about his plus splitter yet. Like the fastball, this is a pitch he throws with remarkable accuracy. Splitters are hard to command – many pitchers’ splitter heatmaps look like giant blobs, and nearly 14% of splitters are wasted, the second highest of any pitch type. But Imanaga repeatedly hits the area at the bottom of and just below the strike zone, an optimal spot for success. His splitter has a 108 Location+ and 57 PitchingBot command grade, both among the league’s highest.

From a pure shape perspective, Imanaga’s splitter doesn’t particularly stand out. It doesn’t have absurd lateral movement like Kevin Gausman’s or fall off the table like Jordan Hicks’; Imanaga’s actually drops a few inches less than average. But when paired with his high fastball, that splitter becomes downright nasty. Thrown from the same release point and angle as his heater, Imanaga’s splitter gets hitters to swing at what they think is a meaty fastball before they have time to realize that the pitch is 9 mph slower and 19 inches lower. He throws it only about half as often as his heater, saving the split for two-strike counts where hitters are in swing mode. And swing they do, coming up empty nearly half the time they offer at it. The end result is that Imanaga’s splitter is one of the best whiff pitches in the league.

The splitter has also been integral in maintaining Imanaga’s minuscule walk rate, as hitters swing and miss at them before they can work themselves into deep counts. Opponents have swung at 47.2% of the out-of-zone splitters he’s thrown, a huge reason his overall chase rate nearly tops the charts. His low walk rate and refusal to waste pitches has worked wonders in terms of efficiency, averaging the sixth-fewest pitches per inning among qualified starters. Imanaga’s quick work of opposing lineups has allowed him to pitch deep into games (averaging six innings per start) while acclimating to more frequent outings as part of a five-man rotation.

Just a month into his MLB career, Imanaga has exceeded all expectations and emerged as an ace. His brilliant pitch execution hasn’t just proven what he can be at his best, they’ve also calmed concerns about what his downside risk can look like. When he signed, it was easy for skeptics to compare him to other hurlers without big velocity and forecast doubt. But Imanaga has shown that nobody else pitches the way he does.

They don’t have a division lead to show for it, but the Phillies have been one of the top teams in baseball to start the year. Alec Bohm and Trea Turner have carried an above-average offense despite some slow starts from the other usual suspects, and the pitching staff has lived up to its projected excellence, sitting a full win ahead of the field entering play Tuesday. Philadelphia’s substantial investments — from the newly extended Zack Wheeler and the re-signed Aaron Nola to the army of high-leverage bullpen arms — are paying off with interest, with Wheeler leading all NL pitchers in WAR. But sitting just a hair behind him is a teammate who may be having an even finer season: Ranger Suárez.

Suárez first rose to prominence in 2021, a season in which his role transitioned from mop-up reliever to co-closer to the rotation over the course of just a few months. After he recorded a diminutive 1.36 ERA across 106 innings in his breakout year, he earned a permanent spot in the rotation entering 2022. Over his first two seasons as a full-time starter, he’s put up a 92 ERA-, making him a solid mid-rotation arm but a clear step below Wheeler and Nola.

That’s changed this year, as the emergence of Suárez has given the Phillies a third ace to follow up their dominant duo. Case in point: Suárez’s eight-inning, one-run gem on Saturday constituted his worst start in weeks, snapping a 32-inning scoreless streak that included a complete game against the Rockies on April 16. And a quick glance at the numbers shows his superb month was no fluke.

The previous version of Suárez possessed neither plus stuff nor control, instead thriving with a high groundball rate that limited extra-base damage on balls in play. As someone who doesn’t throw hard or spin a hammer breaking ball, improvements to his stuff would need to come from more subtle means than his raw pitch characteristics. If anything, PitchingBot and Stuff+ view his season thus far as a slight step back in that department. But while Suárez hasn’t added a tick to his fastball or learned a new pitch, stronger command and synergy of the pitches he already had have led to big results across the board.

Suárez has a kitchen-sink arsenal, throwing five pitch types with regularity and none more than a third of the time. He most commonly starts hitters off with his sinker, a tumbling seam-shifted wake offering with just 4.5 inches of induced vertical break, which is less than half the league average. It’s doesn’t miss bats, but it has enough run to miss barrels; it’s his best groundball pitch and has a negative average launch angle. It’s also a called-strike machine when Suárez lands it in the zone, which he does about two-thirds of the time.

After getting ahead in the count, Suárez likes to pivot to his curveball and changeup, the latter of which has elevated his performance the most this season. The synergy between any groundballer’s sinker and change is crucial to their success – hitters unsure of what’s coming are more likely to both swing over changeups that dip beneath the zone and watch meaty sinkers go by, both good outcomes for the pitcher. Previously, Suárez struggled to locate his changeup, amassing a -5 run value over his first two years in the rotation. But with a +4 value in just six starts in 2024, it’s clear he’s turned a corner with it.

You might not recognize one of the stats in the above table. JOtZ% doesn’t roll off the tongue like BABIP or xwOBAcon, but it stands for “Just Outside the Zone” percentage – a region I defined as outside the rulebook strike zone but in Statcast’s shadow region. The changeups that are thrown just a few inches off or below the plate are the ones most likely ones to draw chases, making JOtZ% a decent indicator of command. In 2022 and ’23, Suárez often missed too low when throwing changeups – directionally correct in hitting his spots, but so low that no hitters were fooled into thinking they were sinkers. By more consistently finding the few inches directly beneath the strike zone, his JOtZ% shot up, and the results followed.

Most hurlers of his archetype struggle to find an out pitch, but Suárez may have two lethal offerings in the bank. In addition to his better-commanded changeup, his already-good curveball creates an enviable package of secondary stuff. He most commonly uses his curve in 0-2 and 1-2 counts as he fishes for strikeouts, often throwing it in the dirt with success. While his changeup’s success relies on pinpoint accuracy, Suárez’ curveball indiscriminately takes down opponents regardless of location thanks to its excellent two-planed break, with over a full foot of drop and sweep compared to a pitch thrown without spin.

Across the league, Suárez is one of just four starters (along with Tanner Bibee, Jack Flaherty, and Jared Jones) with a 19% swinging strike rate or higher on two separate pitches, which makes it no wonder he’s on pace for a career-high strikeout rate. But Suárez gets his whiffs much differently than his competitors do. One of the best indicators of pure stuff is in-zone whiff rate, the number of hittable pitches that batters come up empty on. High-octane aces like Wheeler, Gerrit Cole, and Spencer Strider top the leaderboards over the past few seasons, as do Bibee, Flaherty, and Jones this year. But while his 27.8% strikeout rate is in the top quartile of pitchers, Suárez’s zone-whiff rate sits in just the 8th percentile.

You could look at Suárez’s struggles to earn whiffs on strikes as a sign that his numbers are unsustainable, but I disagree – because what he lacks in in-zone dominance he more than makes up for by controlling the area outside of it. Because most out-of-zone pitches are taken for balls, the median pitcher loses about two runs of value per 100 they throw. No wonder we consider pitches thrown outside the zone to be mistakes. Except, that’s not the case for Suárez.

Suárez is one of just two starting pitchers in the league to create positive value by throwing outside the strike zone. He uses his non-strikes purposefully, each one carefully placed in an attempt to generate a swing from the batter. Data-driven models are a fan of his approach, with his 108 Location+ ranking sixth in the league. So far, it’s worked wonders for his ability to induce weak contact, shattering his previous bests in wOBA, groundball rate, and barrel rate while leading qualified starters in xERA.

More importantly, Suárez’s out-of-zone pitches don’t just keep the ball on the ground; they also miss bats entirely. He throws his curveball and changeup — his two best pitches at getting swings and misses — in the zone just a third of the time; most offerings that earn so many swinging strikes land in the zone far more often than that. Out-of-zone whiff rate is often thought of as a consequence of good stuff rather than great command – the leaderboard over the past few seasons closely resembles the one for strikeouts – but better command can also boost it. Suárez has improved his out-of-zone whiff rate by five percentage points this season, a year-over-year improvement that ranks in the 91st percentile.

All these whiffs on pitches outside the zone are also allowing Suárez to pitch deeper into games. Over his first two years as a starter, he wasn’t exactly known for volume; he would often get into deep counts, which led to a high walk rate and an average of fewer than 5.5 innings per start. Six starts into the new season, he’s bumped that average to 6.8 innings per start without a significant change in pitch count in part because he’s getting more swings on pitches outside the zone. He’s increased his strike rate from 62% to 66% while slashing his walk rate by more than half. More length from him will be a welcome development on a roster that is, for now, rostering just seven (all single-inning) relievers to accommodate a six-man rotation.

We often think of the pitchers with the best command as the ones who dominate within the strike zone – those with the highest zone rate, those who can hit their spots within it, and those who can limit walks — but Suárez shows us that command is different than control (which is something Jon Becker pointed out in his Top of the Order column Monday). Command is about throwing pitches in the spots that induce weak contact, generate whiffs, and befuddle hitters into making poor swing decisions. Suárez’s improved command has taken him to the next level, and he’s done it with a new approach outside the zone.

About two months ago, pitchers and catchers reported to spring training, marking a ceremonial end to the winter and the beginning of a new season. But as players showed up to camp and exhibition games began a couple weeks later, two pitchers were notably absent.

Blake Snell and Jordan Montgomery, our fifth and sixth ranked free agents entering the offseason, each signed contracts dangerously close to the start of the season, with the latter coming off the market just two days prior to Opening Day. Both had to settle for much shorter-term deals than they were expecting, with combined guarantees undershooting our crowdsourced projections by $188 million.

As the first to sign, Snell was the first to make his debut, starting the Giants’ 11th game of the year after pitching in simulated games against his teammates. Montgomery reported to Triple-A, making two starts in Reno before being activated by the big club last Friday. His first start of the year, interestingly, came against the Giants and opposite Blake Snell, so it offered an early look at how this unconventional offseason might have impacted each pitcher.

Snell vs. Montgomery was an exciting matchup thanks to their track records of excellence and the intrigue surrounding their offseasons, but also one that came with many unknowns. How would Montgomery fare in his first major league action of the season? Would Snell bounce back after two consecutive poor outings? How much rust would each deal with after a month of ramp up time?

Snell’s top of the first inning was relatively uneventful; he used his slider and changeup to record three straight outs after a leadoff single. Next, it was Montgomery’s turn to face a Giants lineup stacked with right-handed platoon hitters like Austin Slater and Tom Murphy. Slater led off, and Montgomery’s first offering of the year was a sinker that clocked in at 91.4 mph, two ticks shy of last year’s average. He sat in that velocity band throughout the game, a symptom of the late start to his spring. Slater eventually grounded out on a curveball low in the zone, and the next two hitters were also retired on routine grounders.

Outside of being left-handed pitchers on short-term contracts, Snell and Montgomery have little in common, especially with respect to their pitching styles. Snell refuses to conform to the so-called strike zone, rapidly changing batters’ eye levels with fastballs above it and breaking balls below it. His brand of high-strikeout, high-walk baseball has netted him two Cy Young awards, though he ran a more pedestrian 96 ERA- across the four seasons separating them. Montgomery, on the other hand, prefers to live in the zone with his plus command and arsenal of downward-breaking pitches. He’s never reached the heights of Snell’s peak years, but has outproduced him by WAR over the past three years.

Snell pitched a clean second inning, capped off by a seven-pitch showdown against Gabriel Moreno. After falling behind in the count 3-1, he got Moreno to swing and miss below the zone, then foul off the next pitch to keep the count full. He threw two fastballs and four sliders to get here. So what did he do next?

This is an example of Snell at his best, the version that knows where each pitch is going even when not throwing strikes. Primed for a fastball or slider that would have ended up down the middle had it been aimed at the same spot out of the hand, Moreno went down on a curveball that dropped two feet more than any of Snell’s other pitches. Last season, Snell’s 310 swinging strikes on out-of-zone pitches ranked second in baseball, and most of them came on breaking balls that tunneled well with his fastball before falling off the table.

Unfortunately, Snell failed to execute this strategy for the rest of his start, as too many offerings leaked over the middle of the plate. In the third, a slider and changeup down the middle resulted in loud contact from Blaze Alexander and Ketel Marte. In the fourth, Alexander struck again, this time against the fastball. Snell allowed four more hits in the fifth before being pulled mid-inning, failing to complete five frames for the third consecutive start. The Diamondbacks collected nine hits, the most he’s allowed in a start since 2019.

Most of the hits Snell allowed were the result of the Diamondbacks capitalizing on pitches down the middle, which were uncharacteristically frequent from someone whose pitches tend to magnetize away from the zone. But in this three-start sample, Snell has been leaving more pitches over the heart of the plate, resulting in both more loud contact and fewer swinging strikes in the zone.

While Snell’s command certainly isn’t where it was last year, Montgomery had no such issues locating his pitches throughout his start. He landed an impressive 23 of his 30 sinkers in the strike zone, taking advantage of its high groundball rate; batters have slugged under .375 against in each of the past two seasons. With a strike-stealing machine in his arsenal, many matchups against Montgomery ended in either an early groundout or a pitcher-friendly count that allowed him to deploy his curveball and changeup, the latter of which earned four of his eight whiffs on the night. While he spiked a few curveballs in the dirt, he had excellent feel for locating his changeup, consistently landing it on the armside half of the plate.

Without his typical velocity, Montgomery struck out just three batters (one of which came on a pitch clock violation). Instead, he recorded outs by keeping his pitches away from barrels and limiting the quality of contact against him, tallying nine groundouts in six innings of work while allowing a hard-hit rate of just 32%. Aside from a Jorge Soler homer that marked the only blemish on Montgomery’s record, none of the other batted balls he allowed were particularly threatening; over two-thirds of them had an xBA below .200.

Another trend to watch from Montgomery’s start was his increased use of his changeup and curveball. He’s thrown his fastballs about half the time throughout his career, but he dropped that usage to about 40% in his first game with the Diamondbacks. This shift may simply be the result of good advance scouting — Giants’ right-handed hitters currently rank 28th in wOBA against non-fastballs — but it could also be part of Arizona’s teamwide shift toward more diverse arsenals, especially from its starting pitchers. This season, Merrill Kelly has added a slider to his kitchen-sink arsenal while Slade Cecconi is throwing far more splitters at the expense of his fastball. Montgomery’s curveball has been a successful out pitch and could potentially generate even more outs if he continues to throw it 30% of the time; during his career, batters have generated a pitiful .177/.209/.307 line against it.

Montgomery was removed from the game after six innings and 78 pitches, and Arizona’s offense teed off in the late innings of the game, which ultimately resulted in a 17-1 wallop. Both starting pitchers still have more ramping up to do at the big league level, with Montgomery working back to regular season velocity and Snell still searching for his command after three bad outings. That said, I think there’s reason to be optimistic about both pitchers. Even with an 11.57 ERA, Snell’s peripherals are nearly in line with last season’s numbers, and he tends to improve as the year goes on, with a career FIP nearly a run better in the second half of seasons. Montgomery showed off his advanced pitchability despite his diminished stuff, with a possible arsenal change that could lead to improvements.

Earlier today, Meg Rowley introduced this year’s positional power rankings. As a quick refresher, all 30 teams are ranked based on the projected WAR from our Depth Charts. Our staff then endeavors to provide you with some illuminating commentary to put those rankings in context. We begin this year’s series at catcher.

2023 was a big year for our understanding of catcher defense, as Baseball Savant launched new Statcast-based metrics to quantify the value of catcher throwing and blocking, adding to their existing framing data. While evaluators already had a general feel for which catchers could keep the ball in front of them and which ones had cannon arms (and while prior work had been done on the subject at Baseball Prospectus, among other places), Statcast’s new numbers furthered our ability to compare each dimension of catcher defense in terms of its relative importance. We learned that Sean Murphy prevented 16 runners from advancing via a wild pitch or passed ball, and saw how Shea Langeliers‘ elite arm accuracy might make future base stealers think twice before running on him. Read the rest of this entry »