Schalke chief Christian Heidel says they had to sell Leroy Sane last summer.

Sane made his Manchester City debut in Saturday's win at Manchester United.

Heidel explained: "We had promised Leroy he could leave. If it hadn't happened last summer, it would've happened the next.

"The price would've come down.

"Next year there would have been a large difference in the transfer fee because Leroy had an exit clause, and at every home game 60,000 fans would've known: The next year he is in Bavaria. And with each failed dribble it would have meant: his head is already in Munich."