Cooper Hjerpe retires first 12 batters in major league debut

St. Louis Cardinals rookie Cooper Hjerpe made his major league debut on September 6, 2026, by retiring the first 12 batters he faced. The left-handed pitcher achieved this performance following a multi-year recovery period that included two separate elbow surgeries. His debut signals a transition for the Cardinals as the organization seeks to build pitching depth with young left-handed prospects. The team is currently integrating these newer arms into a rotation that includes both seasoned veterans and rising talent. Hjerpe remains part of a broader internal effort to bolster the team's pitching roster through development and health management.

• 11:30 PMSTLtoday.com — Cooper Hjerpe's perfect debut gives Cardinals a peek at their funky future: Cardinals Extra - stltoday.com