Crusaders owner Arun Watkins said Forster’s move to an as yet unnamed Super League club is a sign of the progress the club have made.
“A little less than 10 months ago, the club was predicted to finish third from bottom across the entire RFL elite system and was possibly moments away from going out of business,” Watkins said.
“Fast forward to now, we are league champions, building solid crowds, our fanbase has skyrocketed and our head coach has been asked to step up to a team who last year were two divisions above us.
“That is possibly one of the highest compliments to get. It is with a heavy heart that we must congratulate Carl and wish him all the best for the future.”