Mariners can't get George Kirby, Logan Gilbert back in their rotation soon enough

The Seattle Mariners rode their starting pitching all the way to contending for a postseason spot last season. It was the backbone of their identity, with a league-best 3.38 ERA, the most innings pitched, and the fewest walks allowed per nine innings. It was a rotation built on efficiency, dominance, and reliability.

Fast forward to 2025, and the story is far more bleak. Through the first quarter of this season, Seattle’s starting rotation has fallen from first to 24th in ERA, ballooning to a 4.40 mark. Their innings per start have shrunk from 5.8 last season to just 5.2 this year. And the elite command that once defined them? Gone. After leading all of baseball with just 1.77 walks per nine innings in 2024, they now sit 2st at 3.27.

Mariners’ once-elite rotation is cracking at the seams

The absence of George Kirby has been a massive void. Known for his pinpoint command and low walk rates, Kirby has yet to make his season debut after being sidelined early in spring training with shoulder inflammation.

The good news? His return is coming soon. As reported by Adam Jude of The Seattle Times, the Mariners have been cautious with his workload during his rehab assignment, keeping him on a six-day rotation to ease him back into form. That approach is expected to continue once he rejoins the big-league club, possibly as soon as May 22.

But Kirby is only one piece missing from the puzzle. Logan Gilbert, one of the Mariners’ most reliable arms over the past two seasons, remains in the early stages of recovering from a flexor strain in his pitching elbow.

Gilbert threw a light bullpen session on Sunday — his first since being placed on the injured list — followed by another session on Tuesday in which, per Daniel Kramer of MLB.com, he threw at 90 percent effort. While that’s progress, Gilbert admitted a rehab stint is likely to build his pitch count back up.

Bryce Miller’s regression has become impossible to ignore. After breaking out with a 2.94 ERA last season, his mark has nearly doubled to 5.22 in eight starts this year. His velocity is down and his walk rate is up. Miller has hinted at physical discomfort, but also acknowledged a mental block that’s led to pitching timidly rather than aggressively and his vow to attack hitters with a renewed mentality didn’t translate to results in his latest start.

Meanwhile, veteran ace Luis Castillo showed a troubling dip in velocity during his last outing, raising more questions about his health or mechanical consistency. And fill-in starter Emerson Hancock was roughed up badly on Monday and the Yankees, adding another crack to the foundation.

The numbers paint the picture: 

• ERA: 4.40 (24th in MLB)
• BB/9: 3.27 (21st in MLB)
• Innings Pitched: 224.2 (21st in MLB)

Compare that to last year, when Seattle dominated in every one of these categories. They led MLB in ERA (3.38), walks per nine (1.77), and total innings pitched (942.2).

Without Kirby and Gilbert anchoring the staff, and with Miller, Castillo, and Hancock all struggling to provide consistency, the Mariners have been forced to rely on arms that generate more contact than swings and misses. It’s a recipe that’s led to shorter starts and more bullpen strain

The Mariners’ pitching depth, once seen as an organizational strength, is now being stretched to its limit. The returns of Kirby and Gilbert offer some hope, but the current state of the rotation is a far cry from the dominance that carried this team a year ago.

For Seattle to climb back into contention, they’ll need their health and their stars to return to form. Their young arms will need to take another step forward. Because if this trend continues, the 2025 Mariners might be remembered not for the rotation that once carried them — but for the one that let them down.