Sane, whose contract runs to 2017, has been this season's Bundesliga revelation, scoring four goals and setting up another four as his form carried him all the way to the German national team and his first senior cap last year.
He needed 31 Bundesliga matches -- including 17 this season -- to achieve this, and Schalke have repeatedly said they are not planning to release the player, who had spent six years playing for their youth teams.
"There is no buy-out clause in force for Sane, neither for this winter nor for the summer," Schalke sports director Horst Heldt said on Twitter after media reports of a potential buy-out clause and a possible departure this year.
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Germany's best-selling Bild newspaper also reported this week he had a buy-out clause of 37 million euros ($40 million), meaning a team could offer that amount and sign the player despite his contract with Schalke.
German media have reported interest from top clubs, both in Spain and in the Premier League, for the hugely creative and quick player but Schalke have denied receiving any specific offers.
The Ruhr valley club, in sixth place this season, are under mounting pressure from their fans to hold on to the gifted player after they allowed another youth product -- Germany international and World Cup winner Julian Draxler -- to move to VfL Wolfsburg this season.
(Reporting by Karolos Grohmann; editing by Amlan Chakraborty)
