Pruitt played professional football in the National Football League (NFL), principally at the fullback position, for 11 seasons from 1976 to 1986. He was drafted by the Cleveland Browns in the first round (seventh overall pick) of the 1976 NFL Draft and spent nine seasons with that club. He had five seasons with over 1,000 rushing yards and was selected to play in the Pro Bowl in 1979 and 1980. He also played for the Buffalo Bills for four games in 1985 and for the Kansas City Chiefs in 1985 and 1986. In his NFL career, Pruitt appeared in a total of 152 games, gained 7,378 rushing yards and scored 56 touchdowns.