German wanted at White Hart Lane this month.
Tottenham are to make a third and final offer to Schalke to bring the signing of midfielder Lewis Holtby forward to this month.
The German under-21 international captain is due to become a Tottenham player in the summer after signing a pre-agreement to move on a free transfer at the end of the season when his Schalke contract expires.
But a season-ending knee injury to Brazilian Sandro has prompted Tottenham to try to bring forward the signing of Holtby to this month by buying out the final six months of his contract with Bundesliga side Schalke.
Tottenham have had two bids turned down already with Schalke not willing to budge from their £1.5million valuation, but the White Hart Lane chairman Daniel Levy is now set to meet the asking price before the end of the transfer window, according to the Sunday Mirror.
Tottenham missed out on transfer target Yann M’Vila when the midfielder opted to join Russian side Rubin Kazan from Rennes, and have so far failed in their chase of another central player Willian from Shaktar Donetsk.
They have been forced to call off Jake Livermore’s proposed loan switch to Queens Park Rangers to ensure they have sufficient midfield cover in Sandro’s absence.