Mariners acquire RHP Cooper Criswell

As spring training draws ever nearer, the Mariners have again fortified the group of arms they’ll bring to camp (known around here as The Pitching Pile), acquiring RHP Cooper Criswell from the Mets for cash. Long-tenured sixth (or seventh or eighth) starter Jhonthan Díaz was designated for assignment in a corresponding move.

Criswell, 29, was originally drafted in the 13th round by the Angels in 2018 (obligatory Mariners tie-in: the Angels’ last pick of that draft was Isaiah Campbell from Arkansas, who would return to school and be drafted by the Mariners in the second round the following year). He then spent two years with the Rays and two years with the Red Sox. The Angels brought Criswell up as a starter, but he spent most of his first year with the Rays relieving. The Red Sox moved Criswell back into a starter role, slotting him into the fifth starter role.

Criswell is in an unusual situation: he’s out of options but pre-arbitration, meaning he makes the league minimum. Boston, facing a roster crunch this off-season but not wanting to lose the versatile Criswell, hatched a plan to try to sneak him through waivers: they signed him to a 2026 deal for slightly above league minimum, at $800K, meaning any team that tried to pick him up off waivers would have to pay above the minimum. That plan was foiled, however, first by the Mets, and then by the Mariners, who picked up Criswell when the Mets DFA’d him to make room for Freddy Peralta and Tobias Meyers.

It’s unclear how the Mariners plan to use Criswell, who isn’t exactly the minor-league castoff who usually shows up on the pitching pile. As a starter, Criswell fits the mold of a typical back-end starter. He has four solid pitches: a changeup, cutter, sinker, and a sweeper. He throws the first three pitches about equally, around 30% of the time each. Criswell has an extremely low arm slot, and his changeup has plus drop, as does the sinker; the two, along with the cutter, combine for a wealth of ground-ball outs rather than strikeouts. It’s a familiar profile: the groundball-getting contact manager back-end starter.

The real interest with Criswell is his sweeper, which he doesn’t throw often: only about 10% of the time. That’s curious, because on paper it looks like it should be his best pitch, with a hellacious 20” of glove-side break. FanGraphs’s Stuff+ model has the pitch well into “elite” territory. However, the few times he threw it last season, batters didn’t miss it. In a small sample size, hitters slugged a gaudy .875 on the pitch.

But why not knockout pitch if knockout pitch-shaped?