SEATTLE, January 23, 2026 – The Seattle Mariners have acquired right-handed pitcher Cooper Criswell from the New york Mets in exchange for cash considerations, addressing a need for pitching depth as spring training approaches. The move comes after the Mets designated Criswell for assignment following their acquisition of Freddy Peralta and Tobias Myers from the Milwaukee Brewers.
A Depth Move with potential
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The Mariners bolster their pitching options with a versatile arm who has shown flashes of big-league capability.
- criswell, 29, offers a mix of starting and relief experience.
- Seattle designated left-hander Jonathan Diaz for assignment to make room on the 40-man roster.
- the Mariners’ rotation is strong, but depth beyond the starting five is a question mark.
- Criswell’s $800,000 salary for 2026 was guaranteed despite not yet being arbitration-eligible.
Criswell has a reputation as a serviceable swingman or back-end starter.His moast extensive time in the majors came in 2024 with the Boston Red Sox, where he pitched in 36 games (10 starts) and posted a 4.02 ERA. However, as the article details, he has recently been subject to waivers and assignments, highlighting his precarious position. Players in this situation, having exhausted their options, can either accept an outright assignment to the minor leagues or become a free agent, potentially forfeiting guaranteed salary.
Criswell exhausted his final option in 2025, placing him in a precarious roster position. He agreed to a $800,000 deal for 2026 with the Red Sox, even before qualifying for arbitration, a salary only slightly above the $780,000 league minimum. This was an attempt to discourage other teams from claiming him off waivers and to make him less likely to pursue free agency. However, the Red Sox designated him for assignment in December, and the Mets later claimed him, only to designate him again this week.
Seattle’s Pitching Situation
The Mariners, it seems, were waiting in the wings. It’s believed they signaled to the Mets that they would claim Criswell if he became available. Seattle boasts a formidable starting rotation led by Logan Gilbert, George Kirby, Bryan Woo, Bryce Miller, and Luis Castillo-one of the best in baseball. Though,the depth behind them is less certain,consisting of Logan Evans,Emerson Hancock,and Blas Castano,none of whom have consistently performed at a major league level.
Switch-pitching prospect Jurrangelo Cijntje is progressing through the system, but he has only seven Double-A starts under his belt and hasn’t yet reached Triple-A. Criswell provides a potentially useful arm to add to the mix, though the Mariners’ roster is currently crowded. He could compete for a spot in the bullpen as a long reliever, but that area is also full.
The Mariners’ current bullpen projects to include Andres Munoz,Matt Brash,Jose A.Ferrer, Eduard Bazardo, Gabe Speier, carlos Vargas, Casey Legumina, and Jackson Kowar. Only Brash and Ferrer can be optioned to the minors without risk of losing them,and both are considered valuable assets. Seattle might attempt to pass Criswell, or another reliever, through waivers to create more roster adaptability.
Diaz Designated for Assignment
To make room for Criswell on the 40-man roster, the Mariners designated left-hander Jonathan Diaz for assignment. Diaz, 29, was previously in the mix for rotation depth alongside Evans, Hancock, and Castano, but Seattle evidently prefers Criswell. Diaz has been optioned to the minors several times in recent seasons and has appeared in five major league seasons, totaling 46 1/3 innings pitched with a 4.66 ERA, a 15.1% strikeout rate, and a 12.3% walk rate. He spent most of 2025 with Triple-A Tacoma, posting a 4.15 ERA in 138 2/3 innings.
Diaz will be in DFA limbo for up to a week, during which time the Mariners can field trade offers. He has previously been outrighted and has the right to become a free agent if he clears waivers, though doing so would mean forfeiting his current contract.
