Rovers had been particularly light in defence due to injuries and suspension but have deemed Foster expendable after he was with withdrawn at half-time of the 5-0 defeat to Peterborough last Saturday.
"After discussing things with Stephen it was agreed that it was in the best interests of both parties if we part company," Moore told Rovers' official website.
"I wish him the best of luck in his future.
"It leaves us short in an important position but I hope to bring in a replacement as soon as possible."
- Ian Goodison