Schalke chief Heidel says the club is open to the prospect of signing Chelsea fullback Baba Rahman permanently.
Rahman, 22, moved to Schalke on loan this summer after been told to work on his defending by Chelsea coach Antonio Conte.
There is no option to buy the player outright in the loan deal but Heidel believe the player could be persuaded to stay with the Bundesliga side even though Chelsea wants the player to return to Stamford Bridge.
The Ghana international joined Chelsea from Ausburg last summer but was used sparingly by Jose Mourinho and Guus Hiddink.
