The NFL ended Williams' indefinite suspension Thursday and approved the Titans' one-year contract with Williams. Tennessee also announced in the same release that Williams had been hired as a senior assistant coach for its defense.
The league issued a statement saying that commissioner Roger Goodell cited several reasons for reinstating Williams, including that Williams accepted responsibility for his role in the bounty program, and pledged to never be involved in any pay for performance system and to teach safe play and respect for the rules.
"The commissioner emphasized that Williams must fully conform to league rules and will be subject to periodic monitoring to confirm his compliance," the NFL said in its statement.
Williams, suspended indefinitely in March 2012, is the last person involved in the scandal to be reinstated by the league. New Orleans coach Sean Payton had his suspension lifted Jan. 22.
Saints general manager Mickey Loomis was suspended for eight games and assistant head coach Joe Vitt for six. Four current or former Saints players were also suspended after an investigation found the club had a performance pool offering cash rewards for key plays, including big hits. The player suspensions eventually were overturned.
Williams coached for the Saints between 2009 and 2011 and was hired as defensive coordinator by the St. Louis Rams in January 2012 before being suspended. Williams had been free to look for a new job in the NFL since the playoffs started, and now he is returning to the team where he got his start in the league back in 1990.
The Titans scheduled a news conference for Thursday afternoon with Williams expected to be on hand along with Titans coach Mike Munchak.
"I have known Gregg for over two decades and have seen him work his way up from a quality control coach to a head coach," Munchak said in a statement. "He will bring a great deal of defensive knowledge and energy to our staff. The decision to bring him here only came after going through a thoughtful and thorough process."
How well this move works remains to be seen, but Munchak faces a must-win situation going into his third season as head coach.
The Titans missed the playoffs in his first season on a tiebreaker in 2011 before slumping to a 6-10 record in 2012. Fans have not been happy that Munchak has kept Jerry Gray as his defensive coordinator after a season in which Tennessee set a franchise record by allowing 471 points, gave up at least 30 points in seven different games and ranked 27th in yards allowed.
Munchak previously made only one move on his defensive staff, firing linebackers coach Frank Bush and moving Chet Parlavecchio from assisting with special teams to linebackers coach.
Williams will be working with Gray, the same man he took with him to Buffalo when he was hired as the Bills head coach in 2001 after four seasons as Tennessee's defensive coordinator under then-coach Jeff Fisher. Gray also worked with Williams at the Washington Redskins between 2004 and '07 before Williams worked with the Jacksonville Jaguars in 2008 and then with the Saints.