George Kirby was once the perfect role model for the Seattle Mariners. A pitcher obsessed with the strike zone, who hated free passes, and absolutely believed in controlling the tempo of the game. With a team that treated walk as a crime and fly balls as friends, Kirby was the ideal product of the Mariners ecosystem—and the biggest beneficiary of it.
Until 2025.
No disaster. No disastrous season. But for the first time in his MLB career, Kirby looked… not like Kirby anymore. Things started off-key: shoulder inflammation, a throbbing knee, and his first IL (Infant Loss) in his career. Upon his return, he was immediately “taught a lesson” by the Astros and Nationals, and spent the rest of the season trying to rediscover himself.
The statistics didn’t tell the way of a crisis: 4.21 ERA, 3.37 FIP. But beneath the surface were changes that were hard to ignore.
Kirby was throwing out of zone more often than ever before. His walk rate increased to 5.5% — still low in MLB, but for Kirby, that was a deviation from the norm. At the same time, his strikeout rate also increased. According to K-BB%, he maintained incredible consistency year after year. In theory, everything was “okay.”
The problem was the feel.
Kirby whiffed more, CSW was better, but he was barreled more often. His chases were fewer, but when opponents chased, they couldn’t do anything — until Kirby made a mistake. And in 2025, his mistakes were punished with unusual frequency.
Kirby’s ERA–FIP (0.85) was one of the worst in MLB, and almost unprecedented for a pitcher pitching at T-Mobile Park. With a home field that “swallows” contact like Seattle’s, it’s hard to explain a starter having such bad luck. It wasn’t because he was hit too hard. It wasn’t because of crazy BABIP. But every small mistake comes at a high price.
And then there’s the pitch mix story.
Kirby almost abandoned the splitter—a weapon he learned from Kevin Gausman—because he was uncomfortable after his injury. The changeup was lackluster. The lower arm slot caused the sinker to change shape and made the slider less likely to split the curveball. Was this a tactical adjustment, or a self-defense mechanism of a body not yet ready? No one has a clear answer, not even Kirby.
That’s what makes his 2025 season so hard to read. How much was intentional? How much was temporary adaptation? How much was simply… not fully healed?
What’s certain is that Kirby wasn’t happy. And that matters.
Entering 2026, the signals suggest he wants to reclaim the splitter—reclaim a part of his identity that was forced to be sacrificed. A Kirby with a healthy splitter is a Kirby who can rebuild strikeout play without sacrificing too much contact. A Kirby like that once stood very close to the Mariners’ “ace-hood.”
Perhaps, that first frustrating season of his career is exactly what Kirby needed. A bit of bitterness. A chip on his shoulder. Motivation not from expectations, but from dissatisfaction.
Seattle has seen the best version of George Kirby. 2026 may not be his “perfect” comeback season. But if there’s anything more dangerous than a smooth Kirby, it’s a Kirby trying to prove that the 2025 season was just a turning point—not the destination.
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