George Kirby can put Seattle Mariners over the top

The Seattle Mariners’ starting pitching has been among baseball’s best for the past few seasons. It figures to be once again in 2026.

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The rotation features four All-Stars who have each finished in the top 10 in Cy Young voting. And most of the group is still in their prime or approaching that point of their career.

With so much talent on the staff, it’s been hard to pinpoint who exactly is the ace.

In 2023, one may have said George Kirby during a season in which he posted a career-best 3.35 ERA and led MLB with the fewest walks per nine innings (0.9) and the best strikeout-to ratio (9.05 to 1). In 2024, Logan Gilbert made his case while posting a 3.23 ERA with a league-best 0.89 WHIP, league-high 208 2/3 innings pitched and 220 strikeouts. And in 2025, it was Bryan Woo who turned heads with an incredible run of 25 straight starts with at least six innings pitched on his way to a 15 wins, a 2.94 ERA and 198 strikeouts on the season.

When discussing the Mariners recently with Seattle Sports’ Wyman and Bob, MLB Network’s Jon Morosi said he thinks Kirby is the Mariners starting pitcher who has the most upside moving forward.

“When he’s really going, when he’s really at his peak – and we didn’t necessarily see it from start to finish last year – I still think Kirby has the biggest upside,” Morosi said. “I think Woo was obviously their best a year ago. I just think that Kirby, the way that he goes about his craft and the demeanor, the stuff. I think that when I look at the body and the delivery, there’s a lot of projection and ability to say he is going to stay healthy and be a durable ace for a long time.”

Kirby is looking to bounce back this season after an up-and-down 2025 that saw him spend time on the injured list for the first time in his big league career.

The right-hander pitched just one inning in spring training before being shut down with right shoulder inflammation. He didn’t make his season debut until May 22, nearly two months into the campaign.

Kirby gave up 11 runs over his first two starts, but in his fourth start on June 8 against the Angels, he fanned 14 batters over seven innings of two-run ball. That looked like a potential turning point, but the rest of his season was a mixed bag. He ended up allowing two or fewer runs in 18 of his 27 starts including the postseason, but he also gave up four or more eight times and six or more four times. His 4.21 ERA and 29 walks allowed in the regular season were both the highest marks of his career.

If Kirby is able bounce back with a better year, Morosi believes it could be the key for the M’s to take the next step after falling one win shy of the World Series last season.

“I think he is the person for whom could boost the 2025 performance the most … heading into ’26 in such a way that really does take the Mariners from being a really good team and maybe even a great team to a World Series team,” Morosi said. “… If Gilbert and Woo maintain ‘25 and then we get the best of Kirby, to me, there is not a team in the American League that is better than the Seattle Mariners.”

Hear the full conversation at this link or in the audio player in this story. Listen to Wyman and Bob weekdays from 2-7 p.m. or find the podcast on the Seattle Sports app.

George Kirby can put Seattle Mariners over the top

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