German star Christian Pander has been ruled out of action for 'several weeks'.
The talented left-footer has seen a recurrence of a knee injury sideline him and he could not be missing for some time.
The 25-year-old, who suffered cruciate ligament damage back in 2005, is now set for tests but Schalke already admit it will be at least a number of weeks.
"Christian is injured and I can't say anything on when he will be back in training here with us," Schalke manager Fred Rutten confirmed.
"It looks like this will last several weeks."
Meanwhile, Schalke star Benedikt Howedes has shunned interest from Juventus and Hoffenheim to pen a new five-year contract at the VeltinsArena.