Wishing DJ a speedy recovery ✊ #ChargeOn pic.twitter.com/t0oUxD077S— UCF Football (@UCF_Football) July 10, 2019MORE: Milton takes big step in rehab processThe rising redshirt sophomore came on late in 2018 to replace McKenzie Milton, who suffered a gruesome season-ending injury against South Florida in Week 11. He completed 35-of-61 passes for 526 yards and three touchdowns to one interception in the final three games of the season, adding 107 yards and four touchdowns on the ground.With Mack’s injury — which typically takes 6-12 weeks to heal — Notre Dame transfer Brandon Wimbush will almost certainly begin the season as the Knights’ starting quarterback. Wimbush completed 193-of-382 attempts for 2,606 yards, 20 touchdowns and 12 interceptions over his three-year career in South Bend. He also added 1,156 rushing yards and 16 rushing touchdowns. Central Florida is down another quarterback ahead of the 2019 college football season.Darriel Mack Jr., a key figure in UCF’s quarterback competition, has suffered a broken ankle, the team announced on Wednesday.