Can the Mets take better advantage of Citi Field’s weirdness?

Since Citi Field opened in 2009, Mets hitters have talked about how difficult it can be to hit at Citi Field.

David Wright watched his drives to right-center fall short of the wall, and Jason Bay rolled his eyes at “Citi Field doubles,” balls pulled deep to left that hit off its back-then-higher-and-deeper wall. In 2018, the Mets performed worse at home (compared to their road production) than any team in nearly a half-century.

And so, as the Mets contemplate solving their most glaring problem in 2021 — their inability to hit for power — they must account for the context of their home ballpark.

“When things come out about the lack of slugging, you have to factor in the fact that we do play in a challenging ballpark for 81 games a year,” said Kevin Pillar, who hit nine of his 15 long balls outside of Queens. “It’s affected our numbers at home, it’s affected our numbers overall.”

The overall context is this: Since 2009, the Mets have posted a better home OPS than road OPS just three times. They’ve had a better slugging percentage at home than on the road just three times, none of them since 2011. The club has moved the walls in, it’s installed a humidor, and it’s thought, through different front-office regimes, about why the ballpark plays the way it does.

The 2021 context is not straightforward: It was actually the third season in which the Mets did have a better home OPS than on the road (by nine points, .710 to .701, lifted up by a very strong September in Queens). The slugging edge went to the road, but only by seven points. But during the middle of the season, there was a large separation between the team’s performance at home compared to on the road (their OPS was 40 points better away from home from June through August), and the team finished the season with 22 fewer homers at Citi Field than it hit on the road.

And a newer front office, with a more robust analytics department, is freshly pondering how Citi Field plays so strangely, the possible explanations for its eccentricity, and the potential advantages that can be gained by exploiting it.

The most intriguing aspect of how Citi Field plays didn’t become evident until 2015, when Statcast data became available publicly.

“Citi Field is one of the things I’ve been trying to wrap my head around,” acting general manager Zack Scott said in August (before he was placed on administrative leave later in the summer while awaiting trial on a charge of driving while intoxicated). “The ballpark suppresses exit velocity, which is one of the weirder things I’ve ever seen. It’s not about wind or dimensions. It’s about the ball off the bat.”

“Citi Field definitely suppresses exit velocity,” head of analytics Ben Zauzmer said. “For any given player whose true talent is at a certain bar, you would expect the exit velocities to be lower at Citi Field than at the average park. And what’s fascinating about it is it appears to affect guys in all sorts of different situations.”

Since exit velocity became publicly available in 2015, Citi Field has ranked in the sport’s bottom three in combined exit velo (for both teams) six times in seven years. It was dead last in exit velo in 2018 — that season when the Mets were as bad a home offense as any in 50 years.

It’s a detail that separates Citi Field from some other parks known historically for being unfriendly to hitters, like Tampa Bay’s Tropicana Field and Seattle’s T-Mobile Park. Those teams routinely score less and perform worse offensively at home than on the road, but their ballparks’ average exit velocities are closer to average.

Citi Field’s consistent track record of low exit velocities is in part responsible for what many viewed as a curious decision ahead of the 2020 season: Major League Baseball installed a humidor to store the baseballs at Citi Field. Considering Coors Field in Colorado and Chase Field in Arizona had been the only two parks using humidors up to that point, many assumed a humidor’s only purpose could be to decrease exit velo. That was the result for those two parks.

But the Mets had wondered heading into 2020 whether they had been storing baseballs in too humid an environment in their park, so they used the humidor to establish a more consistent humidity level. The result seemed to work: Citi Field finished in a tie for 10th in the league in average exit velocity at 88.1 miles per hour — almost a half-mile faster than ever before.

That didn’t last into the full season of 2021, though, with average exit velocity at Citi Field plunging back down by a full mile per hour to 87.1 — good for a tie for 28th in the sport with Citizens Bank Park. Only Milwaukee’s American Family Park posted a lower average exit velocity over the course of the season.

“So it’s not the humidor, so what is it?” Scott asked back in August. “Is it the batter’s eye, the mound height? We’ve looked into a bunch of different things to figure out how this is possible. The bat storage? The visiting team travels with their bats, but it’s happening to them, too.

“I’ve asked MLB about it, just trying to wrap my head around it. Ideally, you’d have neutral environments. It’s a more entertaining game. That to me is not about winning or losing but just having a better product on the field that’s more balanced.”

This year, only the Brewers saw a bigger difference in their team’s average exit velocity at home compared to on the road.

“We’re not just talking about certain types of hitters here,” Zauzmer said. “We’re really talking about hitters across the board, that it suppresses exit velocity in terms of why that’s happening. There’s a number of different theories that we’re actually looking into — some we’re more confident in than others — but the decreased exit velocities do appear to be one of the primary drivers of the overall lack of offensive output here.”

And while the hitters themselves haven’t charted seven years of exit velo data, they did notice their issues producing at home this season. They have their own theories.

“From ’19 and ’20, Citi was a much better place to hit,” said Pete Alonso, who hit only 12 of his 37 home runs at home this year. “I’ve hit four or five this year that were taken away. This entire year here, the weather hasn’t been very consistent at all. Because there’s a ton of openings throughout the stadium and a big opening through center, there are winds coming off the bay. That’s part of it, with wind getting trapped in here, because once it gets in it’s a big bowl. I don’t know if there’s any aerodynamic stuff this year because of the changing weather. But it’s for sure interesting.”

“The batters’ box is good, the visuals in the batters’ box are good,” said Pillar. “I think it’s purely the ball carrying in the stadium, whether it’s the humidor, the way the wind comes into the stadium. We’ve got arguably one of the best home-run hitters in the game, two-time Home Run Derby champ, and if you look at his home-road numbers, it tells a little bit of the story.”

“I can’t give you every theory. I don’t want to stir the pot,” J.D. Davis said. “It’s very weird coming from ’19 and ’20. It’s definitely something that we’ve talked about as a group. I know someone asked for an aerodynamics test just to see how the wind swirls or if it gets knocked down by center field.”

Zauzmer said the Mets have “definitely discussed” carrying out an aerodynamics study, but he wouldn’t say whether it has actually been performed yet. Of note, some analysts have partly attributed the dramatic increase in home runs at San Francisco’s Oracle Park to dividers the club placed over the right-field archways, keeping out peeping eyes during the pandemic season but also the wind off the water.

While counterintuitive, Zauzmer didn’t discount the possibility that the wind is affecting the exit velocity readings.

“There’s always two ways of thinking about exit velocity: There’s what actually literally happens in the physics sense at the millisecond, the moment the ball leaves the bat, and there’s how close are we able to actually measure that,” he said. “You could imagine that there is some discrepancy, that these cameras and radars and everything we have are not perfect.”

Alonso’s home-run numbers — 25 on the road, 12 at home — definitely do stand out, especially because that kind of split didn’t exist for him in either of his first two seasons. (Entering the year, he’d hit one more of his 69 career home runs on the road than at home.)

But he’s not the only Mets hitter with distinct home-road splits in 2021.

The change for Davis is especially interesting, because in 2019, he authored the single best home offensive season a Met ever had at Citi Field. And even this season, he had the highest average exit velocity at Citi Field of any New York regular — one of the only Mets to hit the ball harder at home than on the road.

Davis said not seeing some well-hit balls travel well early in the season this year may have played with his plate approach.

“It’s like golf and driving a ball: You know when you get it. We know when we barrel it up, and we’re like, ‘How the hell did that not get out?’ It’s definitely different and takes a little bit of a toll. You try to stay short and try to get more base hits than trying to hit homers,” he said. “It’s sort of going for more of a line drive (than a fly ball).”

This can be concerning. When a home park plays extreme enough to merit the kind of adaptation Davis is talking about, those changes might impinge a player’s production on the road as well. Think of the Rockies hitter who grows accustomed to breaking balls breaking less in high altitude and then has to contend with normal ones everywhere else.

“When an 0-for-4 with a ball that could have been out could have been a 1-for-4 with a homer, that definitely plays with guys’ psyches,” said Hugh Quattlebaum, who served as the club’s hitting coach for much of 2021. “We’ve just got to do the best we can not letting it get too much into guys’ heads. Just keep rewarding and trying to tell them: That’s exactly what you needed to do in that at-bat. You squared the ball up. You’ve got to find the positives every time … Some balls aren’t dropping, a ball that might be out is caught at the wall. So you try to focus on the things that show those are quality at-bats. That’s all you can do.”

On the other hand, there were some Mets who posted much better numbers at home than on the road — and they tended to be the types of hitters Citi Field rewarded early in its history, before its dimensions were changed: gap-to-gap contact hitters with some speed. (A young intern named Tim Britton once wrote a story about Luis Castillo and Daniel Murphy posting huge home BABIPs during Citi Field’s inaugural season, a truly incisive story which unfortunately MLB.com no longer has online.)

McNeil, in particular, has generally performed better at Citi Field than away from it, with a career OPS nearly 100 points higher at home. The problem in 2021 was that his OPS was much lower at home than it had been before, and that his road OPS plummeted entirely.

However, in Citi Field’s middle years, the best performers at home were left-handed power hitters, like Michael Conforto or Lucas Duda.

Of course, I’ve gotten this far without mentioning the bellowing pink elephant in the room: Despite these protestations from its hitters, New York was 47-34 at home and just 30-51 away from it. It tied for the ninth-best home record in the majors, along with the seventh-worst road record.

So there’s an entire flip side to this coin — one that helps explain that discrepancy: Mets’ pitchers were almost universally better at home, and the team posted the sport’s fifth-best home ERA in 2021 (compared to 13th on the road).

This is one way the Mets are already taking advantage of Citi Field, though again, there doesn’t seem to be much rhyme or reason to who excels in Queens and who doesn’t — and those road numbers are outlandishly bad for some otherwise good pitchers. It’s another point where deeper research into how the home ballpark plays could create marginal advantages in player acquisition and player development.

All these data prevent the Mets from coming to a straightforward conclusion. Yes, the exit velocity is suppressed at Citi Field. No, the team hasn’t figured out precisely why that is, and it hasn’t noticed a meaningful way in which that suppression is distributed. There might not be anything meaningful to be discerned from it. As Zauzmer said, if the park affects everyone the same way, then it doesn’t really matter.

But if there is something underlying it all, if the Mets solve the puzzle and figure out what’s going on at their home park and how they can exploit it moving forward, that can become an enormous advantage.

“You actually can build a team around your park,” Zauzmer said, citing short-porch homers in the Bronx, wall-ball doubles in Boston and ground-ball pitchers in Denver. “Where it can help a team is if you come up with discoveries that it actually plays differently for different types of players, then you can start to figure out: Well, who are guys that could really thrive on the New York Mets?”

(Photo of Pete Alonso: Mike Stobe / Getty Images)