The Mariners have made it clear; they don't want to trade any of their starters
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The Seattle Mariners have two big holes to fill heading into 2026, in terms of their infield and their lineup. Second baseman Jorge Polanco signed a two-year contract with the New York Mets, and talks with free agent third baseman Eugenio Suarez have stalled. But, while team president Jerry Dipoto and general manager Justin Hollander have been desperately trying to make some trades, they don't want to disturb their established rotation. Not even for Brendan Donovan.
This was the same assessment made by MLB columnist Erik Anderson in a story for Heavy, where he points out that multiple members of the media are aware that the M's arms are off-limits.
"If the Mariners are truly drawing a line at 'no established MLB starters, the trade conversation becomes more narrow and more prospect-driven," Anderson wrote. "That can work — especially for a team like Seattle that’s consistently been praised for pitching development — but it also means St. Louis has to be comfortable taking younger arms rather than the kind of immediate rotation help it’s been linked to seeking."
"The other key dynamic: the market. Multiple teams have been connected to Donovan, which can keep the asking price elevated and prolong the process into January and February. A report from The Athletic suggested Seattle and San Francisco were frontrunners to land Donovan."
Mariners Rotation is likely to improve in 2026
In 2025, the Mariners’ rotation was a mix of both experience and potential, with the farm system seeing the fruits of their labor. Luis Castillo emerged as a consistent innings eater. The righty with the blazing fastball, a solid 11 wins and 162 strikeouts with a commendable 3.54 ERA. The 33-year-old veteran was the anchor of the staff, consistently giving the Mariners a chance to win every fifth day.
Bryan Woo is certainly untouchable following his career-making season of a year ago. The 25-year-old went 15-7 with a 2.98 ERA and 198 strikeouts, finishing fifth in the American League Cy Young Award. Unfortunately, he was sidelined late in the season with a nagging pectoral injury. It forced him to miss several starts at the end of the schedule and in the playoffs, but his prognosis for 2026 is 'all systems go'. So, while Castillo spent years as the number-one stunner on the staff, it's pretty clear that Woo has stepped forward to be the Mariners' top starter and ace.
CLICK FOR MORE: ESPN's Buster Olney says Seattle has faith in Cole Young at second base
Castillo, Woo, Logan Gilbert, and George Kirby all made 23 starts or more in 2025, despite Woo's injury. Bryce Miller struggled, posting a 4-6 record and a 5.68 ERA. He has good stuff, a career record of 74-74, and the Mariners would like to see him reach something like his 2024 campaign, when he went 12-8 with a 2.94 ERA. And finally, Gilbert is a trusted starter who held steady, going 6-6 with a 3.44 ERA.
Two other hurlers help hold down the back of the rotation. Emerson Hancock has a career 4.81 ERA in 162 MLB innings, and rookie Logan Evans posted a 4.32 ERA in 81 1/3 innings last season.
Hollander has expressed several times that he wants synergy in Seattle. He wants to hold together a group in the same way the club established by signing hitters Julio Rodriguez, Cal Raleigh, and Josh Naylor; the Mariners want a chance to see what this team can do together... for at least 162 games.
After that? Who knows. But holding their aces close to their vest is a good indication that they're not ready to put those kinds of cards on the table this offseason.
