The Notre Dame graduate transfer beat out true freshman Dillon Gabriel, who is reportedly expected to receive snaps in the Aug. 29 opener against Florida A&M.
Wimbush was Notre Dame's starting quarterback to begin the 2018 campaign but lost the job to Ian Book early in the schedule.
Darriel Mack Jr., who was also expected to compete for UCF's starting job, is out indefinitely with a broken ankle.
The Knights are already without star quarterback McKenzie Milton, who's recovering from a gruesome leg injury. Milton will likely take a medical redshirt this season in order to retain his final year of eligibility for 2020.