Bryan and Bryce

The Mariners have embraced a new style of pitching development of pounding the zone. How does it play with two of their most promising rookies?

Introduction

The Mariners have adopted a new style of pitching development, with their two prominent rookies being some of the clearest examples - Bryan Woo and Bryce Miller. Along with command artists Logan Gilbert, George Kirby, and Emerson Hancock, Woo and Miller have joined the ranks of low-walk pitchers that pound the zone in Seattle. The approach has worked; the Mariners’ rotation leads the league in overall ERA and walk rate, and is 3rd in starter ERA. As someone who despises giving up walks, I’m a big fan of this approach - nothing allowed for free. I’ll look at how the new Mariner Way has influenced Miller and Woo’s arsenal in different directions while also pointing to potential areas of improvement. 

Their Core Pitches

Fastball

The approach for Miller and Woo hinges on the same integral piece of pitch design: a hard fastball with tons of vertical action. While Miller has received acclaim for his absurd 18.5 inches of vertical movement on a 6 ft release point on his fastball, Woo actually arguably outshines him with an even more ridiculous 15 inches of vertical movement on a 5 ft release point. The goal is to maximize the vertical angle entering the zone (VAA), and Woo’s mark of +0.94° VAA above average is top 3 in the league amongst starters, rivaling starters who dominate that category like Joe Ryan. Miller’s score of +0.42° is still well above-average, but doesn’t fall into that distinguished tier. Also worth consideration is Woo’s extension, which is almost half a foot longer than Miller’s, and Miller’s elite spin rate of 2600 rpm(!), nearly 400 better than Woo’s, and even higher than starters even at significantly higher velocities. Paired with an above-average velocity of 95 mph, it’s clear that both Woo and Miller have fastballs that can reach the upper echelon of the league based on these unicorn characteristics.

Miller’s fastball is incredibly similar to Strider’s in terms of pitch design, aside from the elite velocity of Strider. At the same time, Woo runs a Ryan-esque fastball without the great horizontal movement and command.

They utilize it similarly, creating fly balls and whiffs in the zone’s upper third. But despite far better Stuff+ from Miller’s fastball, Woo’s has actually performed slightly better stuff-wise thus far - Miller’s FB runs a 28.5% CSW as opposed to Woo’s 30% - but Woo has struggled more with its command; he’s walked hitters on it 11% of the time from letting it leak down from the top of the zone, leading to his 7.5% walk rate overall. 

Of course, part of Miller’s worse overall numbers on the fastball, despite its better peripherals, is tied to usage; Miller’s lack of solid secondaries forces him to use his fastball for extraordinary lengths. Famously, against the Rays on June 30th, he threw 53 fastballs out of 61 pitches. Of course, the 122 Stuff+ heater got him 18 whiffs on those fastballs anyway from great location up in the zone. Beast. 

Slider

The sliders are where Woo and Miller truly start to deviate. They’ve gone in different directions, showing an intriguing difference in focus. 

Bryce Miller throws his slider 86 mph and uses a gyro grip. Compared to a sweeping slider (which is different from a sweeper!), gyro sliders have far less active spin and rely on gravity to make it drop rapidly instead. With the lack of active spin, it has virtually no horizontal movement either - it falls straight off the table, creating more balanced platoon splits. As a result, Miller’s fastball and slider only have 6 inches of horizontal break differential, which is one of the lowest I’ve seen. According to this article that goes deep into pitch tunneling, that’s actually in the optimal range of horizontal deviation, much to my surprise. He uses it to steal strikes in the zone, but it doesn’t induce many chases. It also gets hit pretty hard in the zone, which, as his only real secondary, is troubling. It does fine overall vs. LHB, but it’ll make any start with a weak fastball a nightmare vs. RHB.

Woo, on the other hand, throws a sweeping slider at 83 mph. He imparts 6 inches of vertical break and 13.5 inches of horizontal break (talk about polar opposite approaches), giving him a much greater 22-inch difference between the two pitches. While this usually is far too much, Woo’s cutter helps serve as the “bridge” between the two pitches, allowing his slider to still get an 86th percentile chase rate despite a comically low zone rate. The downside is that his platoon splits are far more exaggerated, creating significant problems against LHB, which will be discussed later.

Their Differences - Secondary Selection

Because of their different foundations, they turn to other things for the rest of their arsenals. While Miller has a tremendous fundamental fastball with an elite spin rate and gyro slider, he lacks an overpowering 2nd pitch to turn to, especially to same-handed hitters. Meanwhile, Woo has a great 1-2 punch in the fastball and sweeping slider, but he needs help vs. LHB - his elite duo beats righties with ease but offers little support against lefties.

Bryan Woo - A Clear Path Forward

Sinker 

Woo elects to use a sinker with his sweeping slider and cutter to crush right-handed hitters’ dreams, and it works its magic. Its 31% CSW against RHB is excellent, its hard contact rate is half the average for the pitch type, and it gets groundballs 75% of the time. Advanced metrics view it as the best pitch of his main three (fastball/slider/sinker), although they all are considered above average. Stuff+ finds it to be evidently the best, and its command is also exceptional - its ability to find the edge of the zone 45% of the time is excellent for a pitch with the explicit function that the sinker has - to be a pest. While it’s an outstanding pitch, it doesn’t do much to fix that LHB problem. On 11% usage against opposite-handed hitters, a 26.3% CSW% isn’t going to cut it, and neither is his 30% hard-contact rate - it isn’t a contact mitigator in that instance. At least it generates more whiffs than the fastball against them? Tough times. 

Cutter

He’s added a cutter to pair with the sinker, and it does not experience the same success in its 10% usage rate vs. left-handed hitters. He struggles to get it on the inside corner to LHB, and gets virtually no chases on the pitches that do miss. It’s a work in progress, but a pivotal one - the pitch’s success may determine his future outlook - remember, the slider’s tunnel and his performance on LHB may depend on it. 

Conclusion

His command is somewhat inconsistent on the fastball, but he has already shown immaculate command with his sinker and the ability to get slider whiffs. If he can keep his fastball up, he can significantly abuse its elite lift against both sides of the plate, and embrace the Mariner Way of pounding the zone for lots of Ks and very few walks. 

He’s played with both the recently discussed cutter and changeup (I didn’t mention it because of how poor it’s been) in his audition for his ‘beat LHB’ pitch, and I think one will have to come into the picture as a significant force to be dominant long-term. My guess would be the cutter - I think it fits too perfectly with that already-dominant slider and sinker. Josiah Gray knows what’s up.

His current struggles vs. lefties are too much of a problem for him to ignore through the 

offseason, though. His current OPS vs. RHB? .387, which is frankly absurd. Against LHB? 1.041, which is also… absurd. His wOBA vs. RHP is best amongst all pitchers with at least his number of innings - Glasnow is 2nd amongst starters, and around 50 pts of OPS lower. Against LHB, he’s 6th worst, in the company of Luis Cessa and Zach Plesac, who barely even pitch anymore. He could remain below-average against LHB and still be a top-20 starter because of how well he handles same-handed hitters. Watch out for Woocifer. Yes, I made that name up myself. Some of the Mariners’ alternate logos do have a trident in them, you know. 

Bryan Woo might be the most underrated young pitcher in baseball. He has the foundation already to be an above-average arm, and refinement in command and a 4th pitch could let him soar to new heights.

Bryce Miller - Every Possible Option All at Once

Bryce Miller has decided to try to throw every secondary 5-10% of the time and try to confuse the opponent Yu Darvish style. If he doesn’t know which of his 5 secondaries he’s about to throw, how can you? While it may be OK for now, Miller needs a little more than that to reach his elite potential. A brief description of each, in order of usage:

Sinker

8% usage against right-handed hitters, and doesn’t jam them nearly as well as Woo’s. Woo’s runs 2 more inches of drop differential than Miller, which may play a role, but it could be weaker command on that inner third of the plate or the lack of a cutter to pair with it. Either way, it’s worth further exploration. 

Changeup

It runs a 9% usage rate against LHB, and it provides no whiffs, no groundballs, no nothing. 55% rate of landing in the zone (98th percentile) is all you need to know. It does pass the 7/10 rule with a 10 mph difference in velocity and a 10 in. difference in vertical break, but that command will get him nowhere. 

Sweeper

Possessing 18 inches of horizontal movement difference with his fastball, Miller’s sweeper shows Woo-esque potential if paired with a solid cutter. He has thrown a cutter (allegedly), but only 28 times all year, and only according to Alex Chamberlain’s Leaderboard. The other sites claim it doesn’t exist. Bryce Miller has only thrown his sweeper 4% of the time vs. RHB, and while it possesses decent results at the moment, I’m not surprised it hasn’t been used more - it only has a 15% whiff rate and 5% swinging strike rate against RHB. It steals tons of called strikes, but that’s more the element of surprise in the small sample size than the pitch itself, from my view. If he got a cutter going, it’d have a shot of performing with its unique speed range of ~ 82 mph. 

Curveball

Thrown even less than the sweeper, it gets some swings and misses but gets wholly demolished. Without a prominent sweeper, I think there’s simply way too much deviation from the other pitches in terms of movement. 

Bryce Miller covers many areas on the chart, but he needs more reliable performances from his secondaries to relieve himself of too heavy of fastball usage.

(The central purple blob is the gyro slider, and the left purple blob is the sweeper.)

Conclusion

His fastball and gyro slider certainly play, but otherwise, he lacks real direction, given the number of pitches he’s tried at such low usage rates. I guess he ends up with a sweeping slider/sweeper and sinker permanently (sound familiar?), allowing him to dismantle right-handed hitters without the fastball on overdrive. The fastball and gyro slider can manage the lefties.

Bryce Miller has clear potential to be the next Spencer Strider™. He’s got the elite fastball with crazy movement that allows it to see 60+% usage, but he lacks that power secondary(ies) to help him over the line with how much he pounds the zone. Until then, he’ll see a similar inconsistency that frustrates fans given his innate great stuff, similar to Joe Ryan, evidenced by his placement at 8th overall in Stuff+ amongst pitchers with 100+ innings despite a mediocre 4 ERA and 23% strikeout rate. 

Sources:

Alex Chamberlain’s Pitch Leaderboard

FanGraphs

PitcherList

The Mystic Art of Pitch Tunneling - https://www.prospectslive.com/prospects-live/2022/8/23/the-mystic-art-of-pitch-tunneling