Schalke management are nervous about Klaas-Jan Huntelaar's plans.
The Dutch ace is inside the final year of his Schalke deal and has admitted this week he fancies a move to England.
With the likes of Manchester City, Tottenham and Liverpool keeping tabs on Huntelaar's situation, Sport says he won't make a decision over his future until the winter market.
The Dutch will be free to sign a pre-contract with an English club from January 1.