Dietrich underwent arthroscopic surgery to clean up his left shoulder Friday, Bobby Nightengale of The Cincinnati Enquirer reports.
The procedure ends Dietrich's season a few days early but isn't expected to affect his offseason. He'll wrap up his first season in Cincinnati with a career-high 19 homers in just 305 plate appearances, though that came with a startlingly low .187 batting average. He can probably blame some of that on his balky shoulder, though. He was hitting .269/.373/.700 through June 2 but proceeded to hit just .099/.283/.207 the rest of the way.