Cooper HjerpeSTL · RP

2026 review

Cooper Hjerpe worked 4 games in relief for STL, posting a 4.38 ERA and 1.30 WHIP in 12.1 IP with a 27.3 K% and a 16.4 BB% over 55 BF. He was optioned Mar 9, recalled Sep 6, appeared from Sep 6 through Sep 24, then was optioned again Sep 25. Undrafted in NFBC drafts, he finished 586th of 1472 in the TDK LABS 5x5 value rank, 321st of 811 pitchers, and 233rd of 575 relievers. The TDK LABS card tracked a clear swing: on Sep 7 it called his debut in bulk relief impressive, with 4 perfect innings, while flagging his path to consistent value as uncertain; by Sep 19 it noted the scoreless debut had given way to command trouble; and by Sep 25, after he was optioned, it described a piggyback prospect with strikeout rates undercut by heavy walk rates and an uncertain path back.