Multiple sources close to both Louisville and South Florida have verified that Calloway has changed his mind.
The 6-foot-1, 310 pound is rated by Rivals.com as a four-star and is the No. 18 defensive tackle in the country.
Calloway finished a visit to Louisville and decided that USF was the better fit.
Calloway is the fourth player to verbally commit to USF this weekend, following Mike Love from Countryside (Clearwater, Fla.), Hassan Childs from Osceola (Kissimmee, Fla.) and Eric Mayes from Booker (Sarasota, Fla.).
All four players line up on the defensive side of the ball.