Real Madrid midfielder Sami Khedira said it would be tough to leave Real Madrid and pledged to "give everything" as speculation about a move grows.
Khedira, whose contract with the Champions League winners expires at the end of the season, rejected the offer of a new deal last summer and would be available on a free transfer.
Marca quoted the Germany international as saying: "I love Real Madrid. It will be hard to leave this club.
"I will give everything for this shirt until the last day of my contract -- there should be no doubt about that."
At the weekend, Schalke sporting executive Horst Heldt said the club had the funds to bring 27-year-old Khedira back to the Bundesliga.
"He's got many virtues that could be important for Schalke," he said.
"I don't forget that he has played at Real Madrid in the past five years, and not for FC Buxtehude [a small town in Germany's north, used as a symbol for the middle of nowhere].
"He was a starter at Real Madrid and in the national team."
His comments came soon after chairman Clemens Tonnies backed Sami Khedira to move back to German football.