Garcia, 27, will spend eight weeks immobilized in a cast and will miss at least four months of action.
Dr. Mark Lee performed the three-hour procedure at the UC Davis Medical Center.
Garcia, the former first-round pick, injured his forearm while working out Friday.
He averaged personal bests of 12.7 points, 3.4 rebounds, and 2.3 assists in 65 games last season.
Swim Week Miami Beach 2014 [PHOTOS]