Schalke would be prepared to make Brazilian striker Edu's loan move to Greuther Furth a permanent deal.
The forward is with Furth until December and he has become a first-team regular, scoring one goal in seven appearances.
Edu admitted in September he was unsure on his future at Schalke, where he is under contract until 2013, and now the club have opened the door to his sale in January.
General manager Horst Heldt told Bild: "We have not been approached by anyone from Furth yet. We are expecting to hear from the player and we keep waiting on a signal from the club.
"This would make us start talking (about a permanent transfer)."
Meanwhile, Romania international Ciprian Andrei Marica is another player who could be looking to leave Schalke after growing frustrated at his lack of first-team opportunities.
Marica told Westdeutsche Allgemeine Zeitung: "I am far off trying to cause trouble or create confusion. Things are fine for the team and we have a certain competition for the first-team roles.
"But actually I am not as fine as I would like to feel. This is what I have to say."