Borussia Dortmund duo Ilkay Gundogan and Marcel Schmelzer are unlikely to feature against Real Madrid, but Mario Gotze should recover.
The champions of Spain and Germany will meet at the Signal Iduna Park on Wednesday for a top of the table clash in Champions League Group D.
However Gundogan, a deep lying midfielder, and Schmelzer, a dynamic leftback, are doubtful with a back injury and bruised foot respectively.
“As things stand I do not expect to be fit for Wednesday,” Gundogan is quoted as saying.
Gotze missed Borussia's local derby defeat to Schalke on Saturday with muscle problems but is apparently confident of a return.
Gundogan, Schmelzer and Gotze are all German internationals.