Ohio State head coach Urban Meyer announced defensive end Nick Bosa underwent surgery for a "core muscle injury," Cleveland.com's Bill Landis reports.
The Buckeyes do not have a timetable for Bosa's return.
Bosa left Saturday night's game against TCU in the third quarter with what appeared to be a groin injury.
Before his exit, Bosa had five tackles in the first half against the Horned Frogs. His night included a strip-sack that led to an Ohio State defensive touchdown.
The All-American has four sacks and 14 total tackles through three games this season.