The Mariners announced that they have acquired right-hander Cooper Criswell from the Mets in exchange for cash considerations. He was designated for assignment this week when New York acquired Freddy Peralta and Tobias Myers from the Brewers. Left-hander Jhonathan Díaz has been designated for assignment by Seattle as a corresponding move for Criswell. Jorge Castillo of ESPN first reported that the Mariners would be acquiring Criswell. Ryan Divish of The Seattle Times reported the cash going the other way.
Criswell, 29, has the reputation of a serviceable swingman or back-end starter. His most extensive big league look came in 2024 with the Red Sox. He tossed 99 1/3 innings for Boston that year over 18 starts and eight relief appearances, allowing 4.08 earned runs per nine. His 17.2% strikeout rate wasn’t especially high but he limited walks to a 7.2% pace and induced grounders on 50.3% of balls in play.
Despite that solid season, he got pushed down the depth chart in 2025. The Sox acquired Garrett Crochet, signed Walker Buehler and got Lucas Giolito back from his injury absence. Criswell only made seven big league appearances last year. He spent most of the year in Triple-A, where he tossed 65 2/3 innings with a 3.70 ERA, 24.5% strikeout rate, 10.1% walk rate and 49.4% ground ball rate.
He exhausted his final option in 2025, pushing him to a fringe roster position. He and the Sox agreed to a deal in November, guaranteeing him $800K in 2026, even though he had not yet qualified for arbitration. That salary is only marginally above the $780K minimum in 2026.
The hope with a deal like that it would disincentivize other clubs from claiming him via waivers. It would also make Criswell less likely to elect free agency after clearing. He has a previous career outright and therefore has the right to reject further outright assignments in favor of the open market. But since he has less than five years of big league service time, he would have to walk away from the money in exercising that right.
That hasn’t gone as planned. The Sox designated Criswell for assignment in December but the Mets claimed him off waivers. As mentioned, the Mets bumped him off the roster this week. If they had any hope of passing him through waivers, the Mariners presumably called and told them it wouldn’t happen.
More to come.
