After gaining promotion to the Championship with Doncaster Rovers, Sullivan turned down the offer of extending his playing career at the club as well as an Ambassadorial role in favour of returning to former club Leeds United as Academy Goalkeeper Coach on 16 July. With an injury to Leeds substitute goalkeeper Jamie Ashdown, Sullivan revealed he had not officially retired from playing and would be willing to register himself as a player for the 2013/14 season. In the summer of 2014, Sullivan became the First Team Goalkeeping Coach for the 2014–15 season, under Head Coaches Dave Hockaday, Darko Milanic and Neil Redfearn.