The Seattle Mariners have maintained one of baseball’s most formidable starting rotations over recent seasons, a trend expected to persist into 2026. Anchored by a group of talented pitchers, including multiple All-Stars, their rotation has consistently ranked among the best in the league, setting high expectations for the team’s future.
Identifying the Mariners’ Leading Pitcher Amidst a Strong Rotation
Among Seattle’s pitching staff, determining the clear ace has been challenging due to impressive performances from several players. In 2023, George Kirby stood out with a career-best 3.35 ERA, leading Major League Baseball in strikeout-to-walk ratio at 9.05 and allowing the fewest walks per nine innings with 0.9. The following year, Logan Gilbert claimed his spot with a 3.23 ERA, the best WHIP (0.89) in the league, and a league-leading 220 strikeouts over 208⅔ innings. Then in 2025, Bryan Woo captivated fans by making 25 consecutive starts of at least six innings, finishing the season with a 2.94 ERA, 15 wins, and 198 strikeouts.
Expert Insight: Jon Morosi Highlights Kirby’s Potential
MLB Network’s Jon Morosi recently shared his perspective on the Mariners’ pitching, especially regarding George Kirby’s future. Speaking on Seattle Sports’ Wyman and Bob show, Morosi emphasized Kirby’s exceptional upside.
“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’s 2025 Season Marked by Injury and Inconsistency
Kirby’s 2025 campaign was a mix of struggles and flashes of brilliance after facing shoulder inflammation that delayed his season debut until May 22. Limited to only one inning during spring training, the right-hander initially gave up 11 runs across his first two starts. However, in a standout performance on June 8 against the Angels, he struck out 14 batters over seven innings, allowing only two runs.
Despite that high point, Kirby’s season remained uneven. He finished with a 4.21 ERA and a career-high 29 walks, though he limited opponents to two or fewer runs in 18 of his 27 starts, including postseason appearances. Still, he allowed four or more runs eight times and six or more runs on four occasions, underscoring the inconsistency that he hopes to overcome moving forward.
Kirby’s Revival Seen as Key to Mariners’ Championship Aspirations
Morosi believes that if George Kirby regains his peak form in 2026, it could transform the Mariners from a strong team into a World Series contender. With Gilbert and Woo expected to sustain their high-level performances, Kirby’s resurgence might give Seattle the pitching edge to dominate the American League.
“I think he is the person for whom he 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 remarked.
“… 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.”
Additional Mariners Updates and Prospects To Watch
Beyond the pitching staff, Seattle’s roster continues to gain momentum. General Manager comments highlight that prospect Cole Young is “showing us that he’s ready,” signaling confidence in the team’s future talent pipeline. Meanwhile, Jose Ferrer aims to inject energy and effectiveness into the Mariners’ bullpen. Touted prospect Colt Emerson continues to impress in camp, and the team’s top two pitching prospects have attracted close attention from Cal’s program. Also, player Brash reports feeling stronger and more prepared than he has since undergoing surgery in 2024.
