In Bid to Win Cubs Bullpen Spot, Corbin Martin Has Changed a Lot This Spring

The numbers aren't pretty. Corbin Martin has allowed seven hits, four walks and six runs this spring, and he's only gotten 17 outs. He wasn't in pole position for a spot in the Opening Day bullpen, anyway, but it now seems nearly certain that he'll start the season at Triple-A Iowa. Some of those numbers are the results of a multi-layered effort to change his profile on the mound, though. When the time comes—as it always does, for the Cubs, usually by around Memorial Day—Martin could be the guy who's ready to step in and fill vital middle-relief innings for them.

First of all, Martin has moved over on the mound this spring. His arm slot is little altered from last season with the Orioles, but whereas he started on the third-base side of the rubber in 2025, he's on the first-base side this spring:

One reason for that change: Martin is also working to add a sinker to his pitch mix. His natural fastball is a hard cutter, with plenty of ride but considerable glove-side movement relative to most heaters. That shape is unchanged, but Martin is trying to complement it with a sinker that runs much more to his arm side. Moving to the first-base side makes room for that pitch to move across the plate and still be a strike. His changeup also moves a lot in that direction, so two pitches can benefit from the shift in mound position.

When Martin signed, I noted that his best complements for the fastball were a cutter (a more breaking ball-flavored one, which Statcast tagged as a slider at around 91 MPH) and a 12-to-6 curveball to which he switched midseason last year. Interestingly, this spring, he's gone away from that cutter/slider, and back to a slower sweeper-like offering. The curveball is still there, but it's not as sharp as it was last summer.

Keeping that sweeper on the plate from his new place on the mound will be tough. If he can locate the fastball well and tunnel the sweeper off it, he should get a good number of hopeless chases from right-handed batters, but looking at all this, it's not hard to see why Martin has struggled during Cactus League play. He's reinventing himself on the mound, in pursuit of a more complete arsenal that can generate sustainable success in the majors.

All of it could be scrapped, if it doesn't work. Martin could move back to the other side of the slab and pare his mix back down, if erratic outings like Sunday's (0.2 IP, 3 H, 4 ER, 2 BB, 2 SO) continue. However, if he and the team are seeing the progress they want from these changes, Martin might simply need more time to prepare himself for an important summertime contribution.