Bryan Woo’s Repertoire Is The Blueprint For Modern Pitching

This is what the future of pitching looks like.

The Modern Man


In simple terms, Bryan Woo is a shining example of what new-age pitch design concepts artfully crafted into what a modern ace’s arsenal looks like. It’s fun to say but that doesn’t actually tell you anything beyond that he’s a fantastic pitcher and that he’s not “old school.” Excellence as a pitcher comes in a wide variety of forms, that’s one of the best parts of the game. Despite this, there is generally a set number of molds a pitcher can be made from, with some degrees of variation within each individual type, of course. Bryan Woo cares not for these conventions. Instead, Woo displays a rare versatility, as if pulling from multiple molds to expand his ability as a pitcher beyond what most are capable of. To understand what makes Woo who he is as a pitcher, let’s break his work down pitch by pitch. 


The 4-Seam


This is Woo’s bread-and-butter pitch. He throws it 50% of the time, using it when behind and ahead in the count. It’s rare that a fastball is actually good enough to call for this much usage. While I do think he should mix in his other pitches more, this one is an exception where he can get away with such heavy usage. It comes in at 95.4 mph on average, with 14.8” of IVB, and 7.9” of arm-side run. Those of you who have read these kinds of articles before or who know pitch design well may recognize that in a vacuum this is not particularly special movement for a 4-seam. It’s below average in its vertical break and about average horizontally. The thing that elevates this fastball is where he releases the ball from. At 4’11” off the ground, Woo has a release height a full foot below the average. At this height he actually has well above average vertical movement which, combined with his placement of the pitch (up high), creates a VAA of approximately -3.8°.

Vertical attack angle is how steep the ball is moving down as it crosses the plate. For the most part, with a rising fastball you want to get this number as low as possible (Technically high because it’s a negative number but that’s not the point). The exceptions to that rule are guys like Félix Bautista, Pete Fairbanks, and Justin Verlander who release the ball so high, around 7’ off the ground, that the steepness the ball comes down at, combined with the vertical movement they induce to fight gravity’s effect on the pitch creates a unique look that hitters don’t know what to do with.

I’m getting off track, Bryan Woo’s -3.8° VAA is exceptional and puts him ahead of more traditional rising fastball monsters like Spencer Strider and his fellow rookie Mariner Bryce Miller. He’s not the only pitcher to recognize that 4-seam VAA can be cheated by releasing the ball lower than other pitchers: Luis Castillo, Joe Ryan, Freddy Peralta, and the list goes on. There’s a reason not everyone does this though. For one, some guys just aren’t built to release the ball from a lower slot. Furthermore, the lower you release the ball, the harder it typically is to induce vertical movement. Woo’s gift for spin manipulation allows him to create movement that is divergent from the direction the ball spins coming out of his hand. This adds a further wrinkle for hitters trying to track the pitch and pick up spin, only for the ball to move a bit differently than they’d expect. Essentially, Woo’s primary fastball is non-traditional but awesome, and its high whiff rate is evidence of that.



The Sinker


While his other fastball is the superior pitch, Woo’s sinker is nothing to scoff at and it’s part of what makes him so special. He throws it 95.3 mph on average, with 6.2” of IVB, and 16.7” of arm-side run. He also near-perfectly replicates his average release across his fastball– within fractions of inches both vertically and horizontally. Despite the lower release taking away from the steeper VAA you’d hope for on a sinker, this is still an excellent pitch. Earlier on I mentioned that Woo pulls from multiple skill sets in a way that is uncommon. This pitch is the first example of that.

Seam-shifted wake sinkers are very in vogue right now, the answer to the rising fastball for pitchers who can’t throw them. By throwing the sinker with a specific grip, a pitcher can manipulate the ball to change its spin direction in flight, causing it to drop and run more than it would have otherwise. However, having the aptitude to do this at an elite level is usually mutually exclusive with having a rising fastball. This is because SSW pitches tend to agree more with pitchers who have a supination bias while rising fastballs tend to be more of a pronator’s skill. As we previously established, Bryan Woo has an excellent rising fastball. See what I’m getting at? With his unique way of creating a great bat-missing 4-seam, he can get the best of both worlds. Woo’s sinker has an observed movement direction of 2:14, which is vastly different from the initial 1:27 spin direction it leaves his hand at. His 4-seam spins on almost the same axis (1:24), yet its movement direction is at 12:56. This allows him to make his fastballs play off of each other because they look almost exactly the same out of his hand, but have a massive movement difference.

Back to the sinker though, the extreme difference between spin direction and observed movement makes it difficult for hitters to track and can lead to some awkward swings that beat the ball into the ground, assuming they don’t get tied up and miss it entirely. It’s a great pitch that he can use to tie up or induce ground balls against right-handers. It’s probably good enough that he could throw it to lefties but there’s not much point considering the rest of his arsenal.



The Sweeper


If the first two pitches weren’t enough fun, Woo’s breaking ball of choice also happens to be flashy and new-age. Sweepers aren’t a new pitch on their own, it’s just a new name to help differentiate between gyro sliders with little horizontal movement and sliders with a lot of horizontal. So what makes Woo’s so special? He throws it with some power behind it, with an average velocity of 83.5 mph and 13.4” of glove-side break, while again creating the same average release point as his fastballs within a couple of inches— a solid foundation but nothing mind-blowing. Where Woo’s sweeper sets itself apart and into a realm of unique, developing pitches is that it has 6” of positive IVB.

Yes, it’s a rising sweeper. These fascinating breakers are a bit of a newer discovery, and their ability to miss bats and cause weak contact has caught the attention of modern-minded pitching coaches and development programs. The best examples of this pitch thrown by pitchers with normal-ish releases (i.e. not Tyler Rogers or Adam Cimber), are probably Paul Sewald, Colin Holderman, and Steven Wilson’s versions. While Woo doesn’t quite get the same rise as those guys, he gets more than enough to confound hitters as his pitch comes to the plate, both sweeping and fighting against the depth you traditionally associate with a breaking ball. It should come as no surprise after hearing about the first two pitches but Woo also manipulates the spin on this one quite well, creating 1:13 of deviation between the spin direction and observed movement. Most importantly, It follows one of the most essential tenets of pitching to a tee, do something different that hitters aren’t used to seeing.



The Cutter


I’ll be honest, this is probably the least cool pitch that Woo throws. Even so, it’s a solid gyro cutter that functions both as a whiff and a bridge pitch. This is not a traditional fastball-type cutter, it’s more akin to a slider. He throws it 88.2 mph with 4.7” of IVB and 3.5” of glove-side break. While it’s not quite in the range of elite gyro pitches with pure bullet spin, it’s a really solid offering reminiscent of the slider his teammate Andrés Muñoz throws. While he doesn’t quite have the veto to make it play up even further the way Muñoz does, it’s still a good pitch that he can throw out of the zone for whiffs or use to try to set up one of his other pitches, namely his sinker or sweeper.




The Changeup


Woo’s last pitch* is a fledgling changeup that flashes great shape but he doesn’t have confidence in it or control over it yet. He throws it very hard at 89.5 mph, with just 2.3” of IVB, and 13.2” of glove-side fade. In what should come as no surprise at this point, his release point gives away nothing as to what pitch is coming and he achieves exceptional movement on this pitch via spin manipulation. There are a lot of things that can make a changeup good. Some are measurable, such as a velocity or IVB gap between it and the fastball, and some are less easily perceived, such as how deceptive it is to the hitter. With Woo, we know at the very least that he has a large gap between his 4-seam and changeup in terms of vertical movement. 10” of IVB tends to be a mark to strive for and he clears that easily with 12.5” between the two averages. It shows signs of being a great pitch that can make lefties look foolish but its shape is inconsistent and he can’t seem to locate it yet. It’s definitely something I’d like to see him focus on this offseason.



Where Does He Go From Here?


So I’ve spent the last ~1700 words or so heaping endless praise on top of Woo and it pains me greatly to inform you he is, in fact, not perfect. No, there’s still a lot to work on, and that’s what this section is for. To start with, you may have noticed that I didn’t mention his command much in the pitch breakdowns. That’s because it’s very much a work in progress for the young starter. His walk and chase rates are both pretty good, that’s not the issue so much as fastballs that leak into the middle of the zone too often. His 4-seam is meant to be thrown high but it too often finds itself belt high for hitters. Seeing as he throws his fastballs 75% of the time, you can see how his low walk rate is a bit of a facade, he’s more control over command at this point but his ability to fill the zone suggests that better command is on the way. It’s possible that this issue could be resolved as he learns to repeat his mechanics more consistently. He’s clearly a plus athlete on the mound but his release points are all over the place. Notice I said “average release point” earlier when praising his ability to not give away his pitches with his delivery. His non-fastball pitches are in a worse state than his fastballs, but that’s nothing abnormal. Keep in mind we’re talking about a pitcher with a grand total of 156 professional innings. For him to be as advanced as he already is is somewhat miraculous. 

With that number of innings comes the other unfortunate news that makes Woo less important for the people who are wondering about his fantasy baseball outlook. Woo pitched just 57 innings last year, meaning he’s almost certainly climbing toward the end of the yearly innings limit the Mariners have set for him this season in an effort to keep him from overworking his arm. We’ve already seen it with Eury Pérez being shut down despite not being injured and the Marlins pushing for a playoff spot. Teams don’t want to mortgage their future by pushing their top prospect pitchers too hard. Especially with the Mariners selling at the deadline, I’d expect Woo to get shut down within the next few starts.

Enough negativity though, we’re talking about an immensely talented young pitcher with rare gifts that could lead to him becoming something truly special. He has all the stuff a pitching coach could ask for, it’s just about putting it all together from here. Normally at the end of these articles, I give suggestions on tweaks the pitcher I’m writing about could/should make. For Woo, it’s just about shoring up the command and finding the right pitch mix. Once he has a better feel for his sweeper, cutter, and changeup, he should throw them more so hitters can’t just sit on the fastball. I’m kind of at a loss, it’s rare to look at a pitcher and not find anything they could do to improve their arsenal. I suppose it speaks to the quality of the clay he and his coaches are working with. If that’s anything to go off of, Bryan Woo’s future looks to be very, very bright.


*Please ignore that the movement chart in the sweeper section states that Woo throws a curveball. As of my writing this, he does not. It was a singular pitch that was misread by Statcast. The pitch was a sweeper that slipped out of his hand, which caused it to be slower and move a bit differently than normal. It also missed the zone by several feet, which has been known to cause misreads. If you would like to see it, here’s a LINK to the clip of it

Jack Foley

Jack is a contributor at Pitcher List who enjoys newfangled baseball numbers, coffee, and watching dogs walk by from the window where he works. He has spent far too much time on the nickname page of Baseball-Reference.

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