Scouting Report: John Klein

Summary

John Klein, a 24-year-old right-handed reliever from Brooklyn Park, Minnesota, was optioned to Triple-A St. Paul on May 7, 2026, to make roster room for acquired reliever Yoendrys Gomez. Klein made his MLB debut on Saturday against the Toronto Blue Jays, throwing a perfect inning on 12 pitches. In his second appearance on Thursday against the Nationals, he pitched a scoreless sixth inning but struggled in the seventh, allowing two earned runs on two hits (including a home run) and a walk while recording just one out. His ERA stands at 7.71 after two appearances. At Triple-A, Klein has posted a 7.48 ERA across 21⅓ innings this season. Despite the struggles, he possesses intriguing stuff with a mid-to-high-90s fastball, solid low-80s curveball, mid-80s splitter, and upper-80s cutter.