The St. Louis Cardinals recalled left-hander Cooper Hjerpe from Triple-A Memphis on Sunday, putting the 2022 first-round pick on the doorstep of a major-league debut four years — and one reconstructive elbow surgery — in the making. Right-hander Hancel Rincón was optioned to Memphis after appearing in both games of the series at Colorado.
Hjerpe, 25, was taken 22nd overall out of Oregon State in 2022 and signed for a full-slot bonus of just over $3.18 million. He will wear No. 56 and become the 13th Cardinals rookie — and eighth pitcher — to debut in 2026 once he takes the mound. The club listed him as the organization’s 18th-ranked prospect; MLB Pipeline recently had him 16th.
The promotion is the latest chapter in a draft class that has already sent several players to Busch Stadium. Hjerpe now sits alongside Nathan Church, Jimmy Crooks, Brycen Mautz, Max Rajcic, Victor Scott II and Cade Winquest among 2022 Cardinals draftees who have reached the majors.
Elbow trouble has defined Hjerpe’s professional timeline almost from the start. He needed arthroscopic work in 2023, was limited to 52⅓ innings in 2024, and missed all of 2025 after Tommy John surgery in April of that year. St. Louis still added him to the 40-man roster last November to protect him from the Rule 5 draft.
This season he was eased back across four affiliates. After opening the year on the 60-day injured list, he began a rehab assignment in the Florida Complex League in early June, moved to Single-A Palm Beach, then Double-A Springfield, and finally Memphis on Aug. 4. Across 15 starts he has thrown 42 innings with 61 strikeouts, a 3.00 ERA and a 0-1 record.
The jump to Triple-A is where the stuff has looked sharpest. In five starts for the Redbirds, Hjerpe posted a 0.95 ERA over 19 innings, allowing two earned runs on 10 hits while striking out 27. Left-handed hitters have been especially helpless: a .058 average, three hits and 29 strikeouts in 52 at-bats. Walks remain part of the profile — 17 in those 19 Memphis innings — but the swing-and-miss has been loud enough that the Cardinals were willing to bring him up now.
A late scratch from a scheduled Memphis start on Sept. 4 had already put the organization on notice. With Hunter Dobbins done for the year and other starters on innings watches, St. Louis has been looking for fresh arms down the stretch.
Hjerpe is not a conventional left-handed starter. He works from a low, sidearm slot with a delivery that has drawn comparisons to Chris Sale since his Oregon State days, when he was a Golden Spikes Award finalist after striking out 161 in 103⅓ innings. The fastball typically sits 90–93 mph but plays above that number because of the unusual release height and extension. He pairs it with a sweeping slider that runs away from left-handed hitters and a changeup that works the other direction against right-handers.
Scouts have long framed him as a potential mid-rotation starter or high-leverage weapon if the command tightens and the elbow holds. Command remains the open question after the long layoff. Memphis batters drew walks at a high clip even as they struggled to square him up.
The Cardinals are 71-72, third in the National League Central and still hanging around the edges of the wild-card picture after a 10-7 loss Saturday at Coors Field. Kyle Leahy is slated to start Sunday’s series finale against Colorado. Rincón, whose contract was selected Sept. 1, debuted Friday and worked again Saturday; the two appearances produced seven earned runs in 1⅓ innings, and he was sent back to Memphis after the game.
Hjerpe’s first assignment is not yet public. Given the workload management that has marked his return — he has generally been kept under five innings per start at Memphis — a bullpen look or a short start later in the week is more likely than an immediate Coors Field baptism. Either way, St. Louis will get a first look at a pitcher it has been waiting on since the night it called his name in 2022.
For a club that has spent September cycling through young arms and evaluating who belongs in 2027 plans, the call-up is as much about information as it is about the next series. Hjerpe has already survived the hardest part of the rehab. The next test is whether that deceptive slot still plays against major-league hitters.
