Borussia Dortmund CEO Hans-Joachim Watzke has hinted that Ilkay Gundogan's future is in doubt as the club desperately tries to renew his contract.
The 23-year-old midfielder's current deal expires at the end of next season, and Europe's top clubs are lining up to declare their interest.
Die Borussen may be forced to cash in this summer if the German international continues to stall on talks, with Manchester United, Arsenal and Real Madrid believed to be among those interested.
"It is our absolute desire that, besides Robert Lewandowski, no other regular player leaves the club," the Daily Star quotes Watzke as saying.
"Only in the case of Ilkay Gundogan, we do not yet know how it will turn out. We would love to extend [a contract] with him."
Gundogan is reported to be valued at £25m.
