In 2019, Grainger was 79-for-161 passing for 1,222 yards and 13 touchdowns, with three interceptions. He also rushed for 316 yards and five touchdowns on 93 carries.
Against Georgia State that season, Grainger passed for 311 yards and four touchdowns, and he rushed for 53 yards, in a game the Panthers won 48-42.
Listed at 6-foot-4 and 200 pounds, Grainger would have three seasons of eligibility if the NCAA (as expected) passes legislation allowing players to transfer without losing a season of eligibility.
Grainger joins returning starter Quad Brown, a redshirt freshman who accounted for 2,579 yards and 24 touchdowns in 2020, and freshman backup Mikele Colasurdo as Panthers quarterbacks.
The Panthers were 6-4 this season, including a 39-21 victory against Western Kentucky in the LendingTree Bowl on Dec. 26. Three games were canceled because of issues related to the pandemic.