However, his impressive display in last Saturday’s loss to Bayern Munich has the top-dogs at Schalke waxing lyrical about him.
The Ghana fullback joined S04 last month on a season-long loan, without a permanent option.
Heidel insists the player could yet be persuaded to stay with the right offer to his parent club.
He explained: “His situation is a bit different. Chelsea is a bit more restrictive. In the end it depends then the player on whether he wants to stay with us. “