Due to injuries prop Karl Davies retired from the sport and Dave Petersen signed for Sheffield Eagles without even playing a game for the Bulls.
The first signing of the new season came in the form of fullback or halfback Oscar Thomas from RFL Championship side London Broncos on a two-year deal.
Top point scorer Ryan Shaw also left the club after signing a deal with Super League side Hull Kingston Rovers.
Centre Chris Ulugia also signed for RFL Championship side Batley Bulldogs on loan because he could not join permanently due to visa issues.
Due to the departure of Harry Seijka, injury prone fullback Jake Mullaney also left the Bulls by mutual consent.