Sculthorpe's final game for St Helens was in the 2008 Challenge Cup Final, where he injured his shoulder in the opening minutes. After being injury hit in 2008's Super League XIII with only a handful of games played, St. Helens announced they would release Sculthorpe at the end of the season. He was touted as a potential signing for Salford, or joining up with brother Danny at Wakefield Trinity in time for the 2009 Super League season. However, Sculthorpe announced his retirement from the game on 19 September 2008.