Bulls physio Jamie Pitman has been named as caretaker boss while the club seeks a new manager.
A statement on the official site says the club will seek a successor as soon as possible. Pitman takes over after returning to the club two years ago to take over the physio role from Wayne Jones.
The 34 year old had six years at Edgar Street as a player over two spells, making 182 appearances in total. He was assistant boss to Jimmy Harvey at Forest Green for two seasons in between his final playing stint with the Bulls and his return as physio.