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.
Seattle has a strong rotation but the depth isn’t amazing. The front five of Logan Gilbert, George Kirby, Bryan Woo, Bryce Miller and Luis Castillo is one of the best in the game. But beyond that group are guys like Logan Evans, Emerson Hancock and Blas Castano who haven’t yet proven themselves to be effective big leaguers. Switch-pitching prospect Jurrangelo Cijntje is on the way but he has only seven Double-A starts under his belt and hasn’t reached Triple-A yet.
Criswell gives the M’s a useful guy to add to the mix, though the roster fit is a bit tight at the moment. As mentioned, the club already has five good starters. Criswell could be in the bullpen as a long reliever but the relief group is also crowded. The Mariners currently project for an eight-man bullpen consisting of Andrés Muñoz, Matt Brash, Jose A. Ferrer, Eduard Bazardo, Gabe Speier, Carlos Vargas, Casey Legumina and Jackson Kowar. No one in that group can be optioned to the minors except for Brash or Ferrer and they’re too good to be sent down. Perhaps the M’s will try to pass Criswell, or someone else in that group, through waivers at some point for extra flexibility.
As for Díaz, the 29-year-old began today in the rotation depth group alongside Evans, Hancock and Castano but the Mariners evidently prefer Criswell to Díaz in that mix. Some websites list Díaz as still having a minor league option but he was optioned for extended stretches throughout the 2022, 2024 and 2025 seasons. Teams are sometimes granted a fourth option on a player but only if they don’t have five “full” professional seasons, where a “full” season is defined as 90 active days. Díaz first reached full season ball way back in 2017 and has been fairly active since then, so he shouldn’t qualify for a fourth option.
His major league track record is still fairly short. He has appeared in five big league seasons but with just 46 1/3 total innings pitched across those. He has a 4.66 ERA, 15.1% strikeout rate, 12.3% walk rate and 45.2% ground ball rate. He only made one big league appearance last year, spending the rest of the season on optional assignment with Triple-A Tacoma in the hitter-friendly Pacific Coast League. He gave that club 138 2/3 innings with a 4.15 ERA, 19.8% strikeout rate, 4.1% walk rate and 46.9% ground ball rate.
The lefty will be in DFA limbo for a week at most. The waiver process takes 48 hours, so the Mariners could field trade interest for as long as five days. He has a previous career outright and would therefore have the right to elect free agency if he were to clear waivers.
Photo courtesy of Eric Canha, Imagn Images

This is the guy from the Ed Wood movies
Would have been nice to stash
All along I thought the BLUE JAYS designated Jhonathen Dia for assignment ….
That’s amazing!
By the time spring training ends, he ends up back with the Red Sox due to injuries…
Try embracing positivity. It’s easy and better for the soul.
lol. I know you’re right but a Sox ownership has kicked me in groin each season so that’s why I’m negative.
dewey – I’ve never viewed you as negative.
I think the best way to be is both optimistic and realistic.
Every year I’m optimistic through the offseason and into the regular season. Then by June or so I usually have a good feel as to whether or not they are serious contenders.
So right now I’m thinking Roman could win MVP, Casas could come back strong, Crochet and Chapman could stay healthy, and both the Yankees & Jays could suffer key injuries (I’m not wishing it, I’m just saying it could happen).
There’s always a path to success, no matter how narrow.
dewey – I know you’re just kidding, but with 9 respectable SP’s Cooper shouldn’t be needed.
I’m not counting Harrison, Bennett, Drohan, Sandlin or Uberstine.
Fever, yes I was kidding but I wouldn’t mind Criswell as a possible 13th pitcher. While his ceiling is limited, others are more volatile with extremely low floors and high ceilings. If the Sox need him to be a playoff starter, the team has no shot but as a 13th pitcher, he’d be fine.
dewey – Same here, I’ve always liked Cooper as a depth option. He had some pretty good stretches, I’ll never forget him getting pulled after 4 perfect innings just so Hill could come in and face lefties.
I am hoping this is sarcasm at its finest…
Criswell predicts.. he will pitch for the Mariners in 2026 .
“Ed Wood” anyone?
Seattle had done a good job this offseason acquiring bullpen depth.
Now, if they could get an impact bat, better utility piece and a pair of solid active-roster right-handed relievers…
Hahahhaa aaaaahhhhhhh yea…..
…… would be nice!
-Stevil-
The FA list for an impact/utility bat isn’t very “impactful” at this point.
You talking about tuning back the clock with D. Moore & E. Suarez or w/ the M. Andujar/L. Rengifo type(s)?
Don’t know if a FA RH reliever pair would be noticeably better than whats in the back end now.
Seems the best way to fill in the roster is a trade or 2.
If/when the Birds come down off their high horse, would the prospect capital for 1yr of J. Romero & 2yr of B. Donovan be too expensive?
Define prospect capitol?
Anyone in the Mariners top ten, then I would say yes. Too much for either of their services. Donovan doesn’t move the needle as much as the Cardinals would believe. I think J.dip and co would rather test their youth and see if there is a need at the all star break when the prices for talent solidifies into a better known. The risk is only half a season, by then if both Young and Emerson emerge then Donovan might not even be necessary.
The prospect capital the eventual WS Cubs paid was blasted when they acquired Chapmam. Was it worth it?
Organizations trade prospect capital to increase the odds of winning. That’s why they make win now trades.
Waiting for prospects in minor ball or for their emergence in the show doesn’t move the odds needle, now.
The odds to win are there now and trading that capital increases those odds.
Thank you captain obvious.
He has a chance to be a long reliever. He has been inconsistent but effective at times. Nothing to lose by giving him a chance in training camp.
As a RS fan, decent swingman, sorry to lose him.
Good pickups.
F. Peralta & T. Myers are good pickups for The Mets.
Which good pickups did you like:
A. Freddy Peralta & Tobias Myers
B. Garrett Crochet & Walker Buehler
C. A & B
D. Cooper Criswell & A
E. Cooper Criswell & B
F. Cooper Criswell, A & B
The s was a typo
IIIIIIiiiiffffffffff there are no injuries, I think Legumina is quite expendable.
The other 7 would be locks.
Sounds like a serviceable arm for once! Anybody but Diaz please!
Tough group to crack but i could see Criswell moving again before the end of training camp
Mets regain some of the cash they have MIN for Vidal lol
Baseball has stories of every length—the short story of a single at bat, the story of a season, the story of an era.
But the story of the game is always the story of the starting pitcher. He is there every pitch. All eyes linger on him during the play of the game. His success or failure are typically the most consequential in the game. He stands alone on the mound.
I admire the Mariners for consistently having compelling starters.
Good park for Cooper ground ball guy but has had trouble with home runs survived on weak contact and keeping the ball on the ground. Seattle’s park should help reduce the home run issue.
Jerry shopping at the bargain section of Goodwill again…Every team in the AL west had gotten better they better step up their game..My Mets are looking good!
The Angels would like a word
Jerry turns many of those dumpster divers into good to really good players. We need another bat or one of our highly touted prospects to step up. I am not too worried Jerry has done fine. I also believe if we have a huge hole early in the season he can make a trade. We have the bullets to use if need be. The Ms will fair much better than the Mutts this season and years to come.
Mets have a very good farm system and as good or better starting 9 and tons of starting pitching so they will be just fine
Cooper Criswell, we hardly knew you.
—New York Mets
The pile is pleased
Now we demand a shrubbery!!!!
… shrubberies are my trade, I design and arrange shrubberies, my name is Roger the shrubber!
Good pick !!
Dane “Great Dane” Dunning… Cooper Cresswell… The Pile of Arms keeps piling…
Cooper “Crisscross Applesauce” Criswell
This is just like the Mariners who do their shopping in the discount isles. The numbers of pitchers acquired may turn something up. Quantity has its own quality. Now for everything else needed this may drag out for some time with lower expectations, if you don’t mind.
Trade capital if they play their cards well perhaps before or after they complete a worthy pen. No doubt will see some movement.