It's the second time he has left the club. He appeared to have been suspended by the club already for spending money that hadn't been approved.
He was one of those injured in the plane crash after the Hartlepool game at the start of the season.
Mark Devlin said: "Can I also take this opportunity to thank the many friends, supporters and acquaintances for all the support they have given me during my time at the club and since the aircrash."