Cardinals' Cooper Hjerpe joins elite St. Louis company with debut perfection

St. Louis Cardinals' left-handed pitcher Cooper Hjerpe made his MLB debut on Sunday afternoon against the Colorado Rockies, and he was perfect in relief. Hjerpe relieved starter Kyle Leahy, and the southpaw threw four perfect innings, striking out six batters to help the Cardinals take and maintain the lead against the Rockies en route to a series victory.

The 2022 collegiate pitcher of the year took a circuitous route to the majors due to several injury woes.

The Cardinals drafted Hjerpe with the 22nd overall pick in the 2022 MLB Draft out of Oregon State University. He underwent surgery to remove loose bodies from his elbow on May 30, 2023, but he would return later in the year, making 10 appearances that year and playing in the Arizona Fall League. Left elbow inflammation in 2024 shut down his season in early July, and he underwent Tommy John Surgery on April 15, 2025, thus causing him to miss that entire year.

Hjerpe was healthy throughout the minors this year, making 15 starts and throwing a total of 42 innings this year after starting late in the year on June 5th. He posted a 3.43 ERA with a whopping 61 strikeouts in the minors this year, but his showing in Triple-A Memphis was exceptional. In five starts (19 innings), Hjerpe had a 1.89 ERA and 27 strikeouts.

Hjerpe earned his promotion to the majors after several years of fighting past injuries. The organization has high hopes for the former first-round pick, and him debuting with the Cardinals on Sunday is evidence of their belief in him.

He showed why he's an exceptional pitching prospect on Sunday afternoon, and he put his name in history books with a St. Louis native.

Cooper Hjerpe's four scoreless innings in relief have only ever been replicated by Max Scherzer.

Cooper Hjerpe relieved starter Kyle Leahy in the fifth inning. Hjerpe went four innings in relief, facing the minimum of 12 batters and striking out half of them. He had a 26% whiff rate across the board, but his wicked sweeper had a 38% whiff rate. He got three strikeouts on the sweeper, including one against a right-handed batter.

Hjerpe's four innings of relief without allowing a baserunner is the longest in a debut since Max Scherzer threw 4 1/3 scoreless innings in his debut in 2008. Only one other pitcher has thrown four or more scoreless innings in his debut without allowing a baserunner, and that was Max Kranick on June 27th, 2021.

Being mentioned with Max Scherzer is certainly elite company. When that mention happens on the heels of a four-inning shutout makes it all the sweeter for Cardinals fans.

Cooper Hjerpe's path to the majors has been rough for the 25-year-old. He's now in the majors for the foreseeable future. His time for now will be spent as a piggyback starter while he makes a case to join the 2027 rotation. In the meantime, we'll all get to enjoy watching Cooper Hjerpe leave batters dumbfounded with his whiffleball throws.

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