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.
Notable deaths of 2014 [PHOTOS]
Julius Randle breaks leg during NBA debut