Seattle Mariners' Bryan Woo Reveals He's Working on a New Pitch

Seattle Mariners pitcher Bryan Woo revealed that he's working on a new slider.

He made the revelation in a conversation with Chad Greaby while on a rehab assignment at Single-A Everett over the weekend. He's been out with an injured hamstring.

"I was trying to throw (the new slider) a lot," Woo said. "I've been throwing the two fastballs a lot this year, but I'm always trying to refine the off-speed stuff and make them a little bit more effective. But overall, really happy with how today went."

Woo threw 2.0 innings for the AquaSox on Saturday, surrendering two runs while throwing 45 pitches. The overall results are less important than how Woo actually felt, so his response is encouraging.

With regards to the slider, that's also encouraging. According to Baseball Savant, Woo has thrown a version of a fastball for 80 percent of his pitches this season. He's used the four-seamer at 53.5 percent of the time and the sinker at 26.5 percent. Woo features good velocity (mid-90s), and has good run on the sinker, but no matter how good your fastball is, you have to be able to throw off a batters timing too. Woo has used his changeup, sweeper and slider just a combined 20 percent of the time and certainly doesn't want to be fastball dependent - especially as you get deeper into the season.

Given that Woo only built up to 45 pitches in his rehab start, it wouldn't be shocking to see him get another one and then re-join the Mariners after the All-Star break. If the M's do bring him back prior, he could pitch against the Angels in a series that begins Thursday.

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