BREAKING: St. Louis Cardinals received another major setback to their pitching depth
The St. Louis Cardinals suffered a major setback to their pitching depth on April 15 when it was announced that left-handed pitcher Cooper Hjerpe, their 2022 first-round draft pick currently at Triple-A Memphis, would be out until at least mid-2026 after undergoing Tommy John surgery.
Hjerpe, who was already on the 7-day injured list, has struggled with injuries since turning pro. He had elbow surgery just two months after signing in 2022 and reinjured the same elbow in 2024 shortly after a promotion to Double-A Springfield. When healthy, the sidearming lefty has shown promise, posting a 3.27 ERA and racking up 76 strikeouts over 52.1 innings across High-A and Double-A in 2025. However, with this latest setback, Hjerpe will have thrown only 93.1 innings since being drafted.
This is just the latest blow to Memphis’ pitching staff. Top prospects Tink Hence and Quinn Mathews are also sidelined—Hence on the 60-day IL and Mathews on the 7-day IL—with no firm timeline for their returns.
The Cardinals are hoping Hjerpe can still reach his potential despite his injury history. Fans can’t help but recall the case of Alex Reyes, another top prospect whose career was derailed by constant injuries. While Hjerpe doesn’t have quite the same ceiling as Reyes did, his continued health struggles raise red flags. And although Tommy John surgery often leads to a full recovery, some pitchers never fully return to form.
The team faced criticism for keeping veteran Miles Mikolas in the rotation—especially after he allowed 11 hits and eight earned runs over 2.2 innings on April 6—but that decision might prove wise given the dwindling depth at Triple-A. Michael McGreevy is now one of the few arms the Cardinals can rely on if the big-league staff suffers another injury.
Although St. Louis’ pitching has stabilized after a rough start to the 2025 season, and a six-man rotation may help protect the current starters, the rash of injuries to their young arms is pushing their depth to the limit.