A torn lat muscle last March ended up costing Zack Thompson the entirety of his 2025 season, though the Cardinals left-hander was also dealing with another injury. According to Derrick Goold of the St. Louis Post-Dispatch, Thompson had an arthroscopic surgery on his throwing shoulder in August, described as “a cleanup procedure.” The recovery from this surgery has delayed Thompson’s mound work at the start of Spring Training, though he is playing catch and planning to ramp up his throwing.
It seems like this means Thompson will begin the 2026 season on the injured list, though the fact that he hasn’t already been put on the 60-day IL is perhaps a good sign. A 60-day IL placement prior to Opening Day automatically rules Thompson out of action until at least late May, so the Cardinals might feel optimistic that Thompson will be ready to go at some point within the season’s first two months.
The shoulder surgery adds to this extended setback to Thompson’s career. Now entering his age-28 season, the southpaw has appeared in parts of three MLB seasons since St. Louis selected him with the 19th overall pick of the 2019 draft. After not playing anywhere in 2020 due to the canceled minor league season, Thompson has played only with Triple-A Memphis and in the majors, without much success at either level.
Thompson has a 4.50 ERA over 118 innings in the Show, along with a 23.5% strikeout rate and a 9.3% walk rate. It seemed like he was making headway in his first two MLB seasons, but then struggled to a 9.53 ERA across 17 frames in 2024. In Memphis, Thompson has a 5.92 ERA, 23.94K%, and an even higher 13.9% walk rate. The lefty has worked mostly as a starter at Triple-A, but he has started only 12 of his 52 big league games.
Getting healthy is the first priority for Thompson, but once is ready to resume his career, it remains to be seen if the Cardinals will continue to utilize him as a starter or if he might be entirely slotted into relief work. Given how the Cards are in a rebuild phase, there’s not much risk for St. Louis in giving him more looks in the rotation, to see if Thompson can still be a late bloomer who factors into the longer-term plan. Thompson has one remaining minor league option, as since he spent all of 2025 on the big league injured list, he was never sent to the minors (and thus didn’t qualify for minor league free agency).
