Left-handed pitching prospect of the Cardinals faces season-long injury layoff

The St. Louis Cardinals are grappling with a significant setback to their pitchinghemisphere after it was announced on April 15 that their 2022 first-round pick, left-handed pitcher Cooper Hjerpe, currently plying his trade in Triple-A Memphis, will be out of action until at least mid-2026 due to Tommy John surgery.

Before this, Hjerpe was on the 7-day injured list, and his professional career has been marred by health troubles. He underwent elbow surgery just two months after inking a deal with the Cardinals in 2022, and he suffered another elbow injury in 2024 soon after his promotion to Double-A Springfield. The sidewinding southpaw has shown promise when healthy, compiling a 3.27 ERA across High-A and Double-A in 2025 and striking out 76 batters in 52.1 innings. However, this latest setback means Hjerpe will have logged merely 93.1 innings since being drafted.

This isn't the first time the Memphis rotation has taken a hit. Prospects Tink Hence and Quinn Mathews, two of the Cardinals' top-graded hurlers, have also found themselves on the sidelines. Hence now resides on the 60-day injured list, while Mathews occupies the 7-day IL. Neither has received a definitive timeline for their return.

The Cardinals are eager to see Hjerpe realize his full potential without constant health obstacles interfering. Fans might recall Alex Reyes, a high-profile pitching prospect whose career was negatively impacted by a series of injuries. Hjerpe may not possess Reyes' upside, but an ongoing string of injuries doesn't bode well for his future. Although Tommy John surgery boasts a high success rate in the current day, many pitchers never fully regain their repertoire post-surgery.

The Cardinals have faced criticism for keeping Miles Mikolas on the roster, particularly following a disastrous outing on April 6 that saw him concede 11 hits and eight earned runs in 2.2 innings. However, Mikolas' continued presence might turn out to be a prudent move as the Memphis rotation's numbers dwindle ever further. Michael McGreevy is one of the few arms that the Cardinals can rely upon if an injury were to strike the major league rotation.

The Cardinals' pitching has shown marked improvement after a choppy start in 2025, and their newly instated six-man rotation could help safeguard some starters' health. But with three highly-touted young pitchers simultaneously taking a leave of absence for what appears to be an extended period, the Cardinals' depth is under tremendous pressure.

Enrichment Snippets:

Cooper Hjerpe: The 2022 first-round pick (#22 overall) underwent Tommy John surgery in April 2025, sidelining him until mid-2026. Sources indicate repeated elbow problems since the draft, including an operation in 2022 and an injury in 2024 post-Double-A promotion. Despite the challenges, Hjerpe posted a 3.27 ERA with 76 Ks in 52.1 IP across High-A/Double-A in 2024.
Tink Hence: The Cardinals' No. 2 overall prospect (per MLB Pipeline) landed on the 60-day injured list in 2025. Details remain sketchy, but this follows previous issues, particularly workload management concerns due to his injury history in the minors.
Quinn Mathews: The 2023 fourth-round pick (left-handed pitcher) is on the 7-day injured list following a commanding 2024 season (2.81 ERA in Single-A). Like Hence, specifics about his injury are uncertain. These injuries have added to the troubles plaguing the Memphis rotation.

After undergoing Tommy John surgery in April 2025, Cooper Hjerpe, the 2022 first-round pick for the St. Louis Cardinals, will be sidelined until mid-2026.
Prior to this latest setback, Hjerpe had struggled with health issues since being drafted, with previous elbow surgeries in 2022 and 2024.
The Memphis rotation, which includes Cooper Hjerpe, Tink Hence, and Quinn Mathews, has been plagued by injuries, with Hjerpe and Mathews currently on the injured list.
Despite the success rate of Tommy John surgery, many pitchers struggle to fully regain their repertoire after the procedure, as is the current concern for Cooper Hjerpe.