What’s happened to the Mariners’ esteemed starting pitching?
By Adam Jude Seattle Times staff reporter
What was apparent in the moment has, a year later, become increasingly, and painfully, more pronounced: The 2024 Mariners starting rotation was something special.
Collectively, Seattle’s starting pitchers threw more innings and more quality innings than any team in baseball last season; they posted the lowest ERA in franchise history; and they threw harder than any staff in MLB history.
They were that good.
And their success, looking back, is all the more impressive when juxtaposed with the 2025 Seattle staff, whose injuries and inconsistencies have been a significant factor in the Mariners’ late-season free-fall.
To be fair, the Mariners’ issues have been myriad.
Seattle’s lineup has produced just 4.25 runs per game since the All-Star break. Since then, it has one of the league’s lowest batting averages (. 221) and one of the highest strikeout rates (24.8%) while posting a collective 97 wRC+ (100 is average).
The bullpen hasn’t been spectacular, either; its 4.13 ERA overall since mid-July is just above league average.
But for a club that prides itself on pitching — and operates predominantly on a run-prevention strategy suited to the most pitcher-friendly ballpark in baseball — the results from the starting staff has been the season’s biggest disappointment.
It all starts with starting pitching, and for the Mariners to maintain their precarious grip on the American League’s final playoff position, they need their rotation to turn it around.
Since the All-Star break, Mariners starters have a 4.55 ERA while allowing 1.50 home runs per nine innings, one of the highest rates in MLB.
What’s more, the Mariners are allowing the hardest hit rate (47.7%) and the highest average exit velocity (91.4 mph) of any starting rotation in MLB since the break.
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Once the hammer, M’s starters have become the nail.
The starters’ struggles have been exacerbated away on the road, where they’ve posted a 5.89 ERA in their last 22 starts. The Mariners are 6-16 in those road games entering Friday’s series in Atlanta.
Overall, the Mariners have a 4.69 ERA on the road, which ranks 26th out of 30 MLB teams. (Their 3.40 ERA at home ranks No. 4). They’ve allowed 93 home runs and a .268 batting average against (BAA) in 73 road games. Here’s how that breaks down for the top seven starters this season:
Bryan Woo
Road: 15 starts, 3.58 ERA, 14 HR, .231 BAA
Home: 12 starts, 2.35 ERA, 10 HR, .177 BAA
Luis Castillo
Road: 13 starts, 5.40 ERA, 10 HR, .322 BAA
Home: 15 starts, 2.79 ERA, 11 HR, 25 BB, 83 K, .206 BAA
George Kirby
Road: 10 starts, 5.74 ERA, 8 HR, .285 BAA
Home: 9 starts, 3.16 ERA, 4 HR, .228 BAA
Logan Gilbert
Road: 9 starts, 5.80 ERA, 10 HR, .276 BAA
Home: 11 starts, 2.15 ERA, 6 HR, .141 BAA
Logan Evans
Road: 8 starts, 5.36 ERA, 8 HR, 17 BB, 33 K, .317 BAA
Home: 7 starts, 3.32 ERA, 5 HR, 13 BB, 25 K, .203 BAA
Emerson Hancock
Road: 8 starts, 4.97 ERA, 9 HR, .273 BAA
Home: 7 starts, 6.06 ERA, 6 HR, .270 BAA
Bryce Miller
Road: 7 starts, 5.91 ERA, 5 HR, .265 BAA
Home: 6 starts, 5.46 ERA, 6 HR, .257 BAA
Injuries, certainly, have contributed to the Mariners’ rotation struggles.
The Mariners had a remarkable run of starting pitching health and stability in 2024. That changed early on this season, with Kirby and Gilbert each sidelined for about two months with shoulder and elbow injuries, respectively.
Miller’s season, meanwhile, has been derailed by a bone spur in his pitching elbow. Miller did have an encouraging outing in his last start — two runs over six innings in Cleveland — which the Mariners hope portends a strong September.
What has to be the most worrisome situation for the Mariners is the continued struggles of Castillo, who has insisted his issues are not health related.
The 32-year-old right-hander has a 10.06 ERA in his last four starts, and his fastball velocity has taken a notable dip.
Castillo’s next scheduled start is Sunday in Atlanta for the final day of the nine-game road trip. It’s fair to wonder if the Mariners might consider re-slotting the rotation to push Castillo back a day or two to pitch at home against the Cardinals early next week, but that would just put a greater burden on the other starters.
“He’s been a guy that we’ve been able to depend on, and we still depend on him, and he’s going to figure it out,” Mariners manager Dan Wilson said about Castillo after Monday’s loss in Tampa. “He’s a guy that we love sending him out there, because he’s been in these situations, he knows what to do. We’ve got to keep going with it.”
The Mariners simply don’t have another great option. Hancock has been moved to the bullpen. Evans, a rookie, proved to be a capable fill-in during the first half of the season. But he’s now on the injured list with elbow inflammation, and it’s unlikely he’d be able to return, if needed, before late September.
Woo, the Mariners’ 25-year-old All-Star and emerging clubhouse leader, is scheduled to start when the Mariners, mercifully, return home Monday to open a series opener against the St. Louis Cardinals.
“At this point of the year, you can make all the excuses you want,” Woo told reporters Tuesday in Tampa. “You’ve just got to play better. You’ve got to be better. You’ve got to have more urgency. I think all the guys in the locker room, especially the guys that have been here the last couple of years, are sick and tired of the last couple of years of what has happened in August and September. It’s up to us to flip the script and do something about it.”
The Mariners have leaned heavily on their starting pitchers the past few years. To get back to the postseason, they’ll have to lean on them even more over the season’s final few weeks.
Adam Jude: ajude@seattletimes .com. Adam Jude is a Seattle Mariners beat writer at The Seattle Times. He previously covered UW Huskies football and the Seattle Seahawks for The Seattle Times.