40 in 40 2025: Bryan Woo
We bought a Woo
Here’s a paragraph I wrote about Bryan Woo last spring:
Among the 199 pitchers who faced at least 100 right-handed batters, Woo was third by wOBA. Third! But against lefties, he was 143rd out of 154. That just won’t work, and he needs an answer if he wants to be more than a back-end starter.
The answer I was expecting in 2024 was the answer anyone would have expected: leaning hard into developing an offspeed pitch or breaking ball. I was particularly into the idea that he might fashion a change up modeled after Luis Castillo’s once dominant cambio. And maybe he could develop better command of his slider, which was bad in his rookie 2023 but did have tantalizing moments like in a gem against the White Sox.
Instead, something really weird happened. Bryan Woo just stopped being bad against lefties, almost as if by force of will. He threw his four-seamer and sinker against lefties 70% and of the time and it just . . . worked. Fastball go brrrrrr.
Despite throwing the ball hard and straight all the time, Woo took his K%-BB% against lefties from 6.7% in 2023 to 17.7% in 2024. His results against righties fell back to earth just a touch, so his overall line balanced out a bit, but his rookie-year platoon splits were maybe just a small-sample illusion. Turns out Bryan Woo just kind of rules.
The question is how much of him we’ll see. A string of injuries has repeatedly knocked him off the active roster, and he’s already developing a reputation as a bit of a fragile boy. Yet I think this reputation is overstated. He topped 130 innings in both 2023 and 2024. I’m not saying that makes him a workhorse, but it’s more Tyler Glasnow than Danny Hultzen. For someone who’s “injury prone,” he actually pitches a lot. In today’s game, 130 innings of an 80ish ERA- counts as one of the 50 best starters in the league.
Projections
FanGraphs Depth Charts: 134 IP, 1.8 fWAR, 3.71/3.83 ERA/FIP
PECOTA: 151 IP, 2.9 WARP, 3.52/3.93 ERA/DRA
Over/Unders
Eric: Under
As much as I’m a believer in Bryce Miller, I am the opposite for his buddy Bryan Woo (whenever the two are featured in social media content, it’s a must-watch), but it’s not a skill issue with Woo. He’s got fantastic stuff, but as we all know he’s been limited to fits and starts due to injuries. So, even 134 IP feels mighty optimistic and while I absolutely hope he outpaces that, when it comes to serial injuries for pitchers I cannot agree with such optimism with any real confidence.
Kate: Over
For starters, I think both of these innings projections are low. One thing about getting spoiled with the Mariners’ excellent pitching is we forget that what the Mariners did with Miller and Woo should not have worked. You just don’t get to draft two pitchers in the middle rounds, race them through the minors, and then plop them into a major league rotation without something going wrong. It doesn’t have to go like, Angels starters wrong, but there should be some form of struggle. That’s the struggle Woo had last season, teaching his body in real time what it means to be an MLB starting pitcher. So for that reason, I’m taking the over here, handily.
John: Over
My concerns with Woo’s ability to hold up are ultimately beyond assessment. His delivery is fluid and the Mariners organization is skilled at helping pitchers refine their motion into an efficient angle. Woo’s added ~30 innings to his annual workload every year stretching back to his final year of college, where he threw just 28.0 frames. The goal of around 150-160 innings feels appropriate, and Seattle seems likely to angle for opportunities to still be slightly light-touch on the righty until late in the season.