The Cardinals released Showalter on Tuesday.
Showalter showed initial promise after being acquired from the Orioles in the August 2023 trade that sent Jack Flaherty to Baltimore, fanning 59 batters in 34.1 innings while holding a 2.62 ERA at Single-A Palm Beach in 2024. He's had a difficult time staying healthy and performing since then, however, and had been battered for 16 runs (15 earned) over 8.2 frames this season at High-A Peoria.