The Manchester City contracted defender has just finished a season-long loan stint at Schalke and the club have an option to sign him permanently for £5m.


Schalke want to keep the fan favourite, but they do not want to sign him before bringing in money through player sales, according to German daily Bild.



Schalke have until the end of the month to trigger the £5m option, but they feel if they did that without making a player sale to help cover the cost they could be blackmailed later this summer.


The Ruhr giants feel clubs would know they had to sell and would look to take advantage.



Malick Thiaw, Amine Harit and Ozan Kabak are all attracting attention and could potentially bring in money for Schalke.


Sales are unlikely to have been made by the deadline of 31st May though.



Schalke could try to renegotiate the fee with Manchester City, but the player could end up leaving the club.