 Nick Saban resigned as Toledo 's head coach on February 13 , 1991 , after one season to become defensive coordinator of the National Football League 's Cleveland Browns under Bill Belichick . As defensive coordinator for the New York Giants , Belichick had to postpone assembling his new coaching staff until after Super Bowl XXV . Therefore , Saban 's resignation wasn 't announced until well after the season had ended . Additionally , Saban wanted any potential move to occur after February 6 , National Signing Day for recruits . 
