It's not that unusual in the SEC to see former head coaches at the collegiate level (or even the NFL level) show back up in an assistant's role.
For example, Cam Cameron just finished his first season as LSU's offensive coordinator. He was the Miami Dolphins' head coach in 2007 and served as Indiana's head coach from 1997-2001.
Former Miami coach Randy Shannon is on Bret Bielema's staff at Arkansas. Former Marshall coach Mark Snyder is Kevin Sumlin's defensive coordinator at Texas A&M. Former UCLA coach Karl Dorrell was recently announced as Vanderbilt's offensive coordinator under first-year coach Derek Mason. Former Kentucky coach Joker Phillips is Florida's receivers coach, and Auburn defensive coordinator Ellis Johnson spent one season as Southern Miss' head coach before joining Gus Malzahn on the Plains.
At Alabama, Nick Saban has five former head coaches working under him, counting director of football operations Joe Pannunzio. Prior to going to Miami, his last stop before joining Alabama, Pannunzio was Murray State's head coach from 2000-05.
The newest former head coach on Saban's on-the-field staff is a familiar face and a valuable one. Kevin Steele, who was the head coach at Baylor from 1999-2002, is moving back on the field as inside linebackers coach and will also be a special assistant to the head coach after serving in a player personnel role at Alabama last season. Steele, one of the top recruiters in the business, also coached linebackers at Alabama in 2007 and 2008 before going to Clemson as defensive coordinator.
Steele is one of three coaches on Alabama's 2014 staff who left to go elsewhere and are now back. Defensive line coach Bo Davis returned after spending the last three seasons at Texas. Outside linebackers coach Lance Thompson is on his third different stint with Saban. They were together at LSU in 2002 and 2003, and Thompson spent the first two seasons with Saban at Alabama in 2007 and 2008 before going to Tennessee for three seasons and then returning to Alabama in 2012.
Ironically enough, Thompson was lured away from Alabama following the 2008 season to join Lane Kiffin at Tennessee. Kiffin is entering his first season on Alabama's staff as the Crimson Tide's quarterbacks coach and offensive coordinator. He's one of the five assistants on this staff with head coaching experience, with the NFL's Oakland Raiders as well as Tennessee and USC in the collegiate ranks.
Offensive line coach Mario Cristobal was the head coach at Florida International from 2007-12, while tight ends coach/special teams coordinator Bobby Williams followed Saban as head coach at Michigan State from 2000-02.
Counting current defensive coordinator Kirby Smart, seven of the nine on-the-field coaches on the Tide's 2014 staff have either been a head coach or offensive/defensive coordinator at the FBS level.
Saban, for all the talk about being so controlling, likes having that kind of experience on his staff and particularly likes having guys on his staff who are going to challenge his thinking. It also speaks to his security that he would have so many former head coaches on his staff, not to mention the fact that he's not hesitant to bring guys back.
He has never been shy about tweaking his staff, either. Every year he has been at Alabama, he's had at least one coaching change.