 His loan spell at Colchester United had come to an end, following a conclusion to his loan spell, but willing to return to the club.In 2013, Sullivan signed a loan deal with AFC Wimbledon, until the end of the season and was ever present for the duration of his loan period, including their dramatic escape from relegation on the final day of the league two season.It was confirmed on 30 April 2013 that Sullivan has been released from Charlton.