Fox Sports has reported the deal to be a six year contract.
The 43 year old Pruitt is in his second season at Alabama under Nick Saban, with the Crimson Tide ranked No.1 in the nation in scoring defense and second nationally in total defense.
Plans call for Pruitt to stay on in his role with Alabama through the College Football Playoffs, while also putting together a coaching staff and heading recruiting efforts for Tennessee.
Pruitt is a two-time Broyles Award finalist for the top assistant coach in college football and is considered one of the top recruiters in the SEC.
Pruitt will replace Butch Jones, who was fired after going (14-24) in SEC play and (34-27) overall in five seasons in Knoxville.
A press conference will be held this afternoon at 5:00, with live broadcast on Star 95.1.