Munas Dabbur has suffered a knee injury and may not play again this season.
Dennis Geiger is on his way back from a thigh injury, while Andrej Kramaric is struggling to shake off a nagging groin problem.
Ihlas Bebou is suffering with knee pain, whille Sargis Adamyan faces an operation on his ankle.
Jacob Bruun Larsen joined from Borussia Dortmund and could get a start in attack.
Ishak Belfodil had a knee operation and is unlikely to play again this season according to coach Alfred Schreuder.