Holtby has already agreed to join Spurs in the summer but the north Londoners are keen to push through a deal to bring the 22-year-old to the club early in the wake of Sandro’s season-ending knee injury.
However, the German club’s general manager Horst Heldt insists that the Bundesliga outfit have no intention of letting the midfielder leave on the cheap.
“We are in intensive talks, but Lewis is a young Germany international with the quality that goes with it and you don’t just give somebody like that away for a bargain price,” Heldt told dpa.
Holtby has made 75 appearances for Schalke, scoring 11 times, and has earned three caps for the senior German national side.
Speaking after agreeing to join Spurs earlier this month, Holtby said: “[Tottenham] are not a small club and have an insanely good manager.
“I simply had to take the offer from Tottenham. New things don’t scare me, they excite me. In my opinion Tottenham is a big club in Europe.”