Monte Kiffin, the assistant head coach for defense last season with the Dallas Cowboys, will not return for the 2015 season, according to a report Tuesday.

Kiffin is the only coach on the staff who did not have his contract renewed by the Cowboys with the exception of Bill Callahan, who left after the 2014 season to become the offensive line coach for the Washington Redskins.

Kiffin is turning 75 this month but would like to continue coaching, ESPN reported.

His long career as an assistant included a run with the Tampa Bay Buccaneers from 1996 to 2008 when he produced a top-10 defense in 11 of his 13 seasons and was part of a Super Bowl championship in 2002.

In 2009, Kiffin joined his son Lane’s staff at Tennessee and then went to Southern California for three seasons before he returned to NFL as the Cowboys’ defensive coordinator in 2013.