3 reasons Mariners' Bryce Miller is on thin ice ahead of latest start

Having already secured their first series loss after winning nine straight, the Seattle Mariners will look to avoid a sweep by the Toronto Blue Jays at T-Mobile on Sunday. While it should work in their favor that they'll have Bryce Miller on the mound, this isn't 2024 anymore.

Last year was not only a good year for the 26-year-old right-hander, but one that was even better than many might realize. He led even Logan Gilbert and George Kirby with 3.4 rWAR, the result of him posting a 2.94 ERA over 180.1 innings.

So far, however, 2025 has been a struggle for Miller. Though his 4.15 ERA isn't bad in a vacuum, he's been making Mariners fans hold their breath with every pitch. And given the specifics of his struggles, the team must be wary of whether he should remain a fixture in the starting rotation.

Let's get into three issues Miller is having that should have the Mariners spooked, and what the team might do to get him back on track.

Miller's 1st Major Issue: He can't stop walking hitters

Staying within the strike zone was one of Miller's strengths in 2023 and 2024, as he walked only 2.1 batters per nine innings. It is therefore shocking to see him walking 4.9 batters per nine in 2025.

Miller has issued multiple free passes in six of his seven starts, equaling how many times he did so in 25 starts in 2023. While the good news is that he's finding the strike zone with more than half his pitches, his 50.5 zone percentage marks yet another decline after he finished at 55.0 in 2023 and 53.7 in 2024.

It's hard to put a positive spin on a pitcher walking even one hitter, much less when he's allowing free passes to pile up. This is what Miller has been doing, and it's contributing to excess traffic on the basepaths and more high-stress pitches on his arm.

Miller's 2nd Major Issue: His fastball isn't fooling anyone

Though Miller finally put up a goose egg in the walk column on May 5 in Sacramento, traffic on the basepaths remained an issue. He allowed seven hits and hit a batter in only 4.0 innings of work.

Athletics hitters notably batted .300 with an 8.3 whiff percentage against Miller's four-seam fastball. Such a performance would have been a mere blip in 2024, wherein Miller's heater was the most valuable pitch on Seattle's staff. But in 2025, the fastball has been a persistent underachiever.

Its reading are down across the board, including with a 0.8 mph drop in average velocity and a 7.4 percent drop in whiff rate. Miller himself seems to have gotten the message, as he notably shied away from his heater by throwing it just 35.1 percent of the time on May 5.

Miller's 3rd Major Issue: He's not missing bats

On a per-nine basis, Miller's strikeout rate has barely budged from 2024. He fanned 8.5 batters per nine innings last year, compared to 8.3 this year.

Yet his actual strikeout percentage — i.e., as a share of batters faced, not innings pitched — is down from 24.3 to 21.5. His contact rates have likewise taken a turn for the worse, and it's not a case of him trading the occasional swing-and-miss for the occasional soft-hit ball.

His average exit velocity is up from 90.3 mph to 91.1 mph and he's getting ground balls at only a 34.4 percent clip. T-Mobile Park will shield him from the worst outcomes of this combination of factors, but it's still not what any team wants out of a supposed top-of-the-rotation starter.

What can the Mariners do with Miller?

With injuries having taken first Kirby and then Gilbert out of the rotation, the Mariners haven't had much choice but to remain patient with Miller. And he indeed hasn't been 100 percent in his own right, as he's pitched through both a sore arm and a sore back.

Yet with Kirby likely to return sometime this month and Gilbert potentially able to follow suit, Seattle's rotation is going to get crowded in the not-too-distant future. The Mariners will have to sideline one of Miller, Luis Castillo, Bryan Woo, or Emerson Hancock. It's obviously not going to be Castillo or Woo, and Hancock has shockingly turned into one of the team's most reliable starters.

Given his soreness issues, the Mariners may have cause to put Miller on the injured list so he can get to full health. The club could otherwise hope to spur a reset by moving him to the bullpen or optioning him to the minors. Either would be shocking, but the latter would potentially be more beneficial. It would put him in a lower-pressure environment in which he could iron out kinks, such as a release point that is suddenly higher than it should be.

Or, the Mariners could keep Miller in the rotation and hope his issues work themselves out. Though this is the uncomplicated route, it would be a case of the team testing the classic definition of insanity: Doing the same thing over and over again and expecting different results.