Turner was forced off against Middlesbrough on Saturday having taken an ankle knock whilst Marcus Hall was replaced at half-time with a knee injury.
Ben Turner
Elliott Ward and Patrick van Aanholt are on standby to replace them.
For Watford, Icelander Heidar Helguson is out with a calf injury whilst Jay Demerit is out with an eye injury. Scott Severin is back in training but is not expected to play any part in the game which kicks off at Vicarage Road at 7.45pm.