Mariners ace Bryan Woo is MLB's perfect pitching machine

When Seattle Mariners starting pitcher Bryan Woo takes the mound this Saturday against the Texas Rangers, it won't just be another start — it will be a continuation of one of the most quietly dominant pitching performances in Major League Baseball this season. In a year where Seattle’s rotation has been riddled with injuries, Woo has been the one to stabilize the staff.

The Mariners, long known for their deep and durable starting rotation, have faced unfamiliar turbulence in 2025. Logan Gilbert, George Kirby, and Bryce Miller have all spent time on the injured list, with Miller still working his way back. That left Seattle needing more than just innings — they needed excellence. And Bryan Woo has delivered.

Woo has gone at least six innings in all 15 of his starts this season — a sign of durability and efficiency that would be impressive under any circumstances, but especially amid the uncertainty swirling around him with his own injury history. His steady presence has transformed him from an intriguing young arm into the clear ace of the staff.

The numbers back it all up — and then some.

Amid injuries, Bryan Woo has emerged as the Mariners’ true ace

Since the start of last season, only the Detroit Tigers' Tarik Skubal has gotten more total run value out of a four-seam fastball/sinker combination than Bryan Woo. Skubal clocks in at 40 runs saved. Woo? Right behind him at 39. That's elite territory, not something you’d necessarily expect from Woo’s raw metrics. His fastball velocity sits in the 69th percentile, and his spin rate is actually below average at the 45th percentile.

So how does that work? The magic lies in his delivery. Woo generates a low release point paired with excellent extension toward the plate, creating a fastball profile that plays way better than it looks on paper. It gets on hitters quickly and rides through the zone with late life, making it hard to square up.

But Woo’s dominance isn’t just about pitch movement — it’s about relentless pressure. He leads all of Major League Baseball in zone percentage, throwing pitches in the strike zone 59.8 percent of the time. He’s not nibbling at the corners. He’s going right after hitters — and more often than not, he’s winning those battles. That’s a higher clip than 2023 George Kirby, whose strike-throwing mastery (56.6 percent) helped him land an All-Star nod and a top-10 Cy Young finish.

At this rate, Woo is following that same path — maybe even a better one. His confidence, command, and ability to rack up efficient outs has placed him in elite company. And while there’s still a second half of the season left to be played, the first half has made quite the statement.

He's becoming the exact type of pitcher every team dreams of. One you can pencil in for six strong innings, elite fastball performance, and absolute command of the zone every time out. The perfect pitching machine. And for the injury-plagued Mariners, that machine is powering their run at clinching a playoff berth.