Tottenham Hotspur have offered €1m (£840,000) to Schalke to bring forward the transfer of the attacking midfielder Lewis Holtby from the summer to this window but the German club are holding out for €2m.

André Villas-Boas, the Tottenham manager, has agreed a pre-contract for Holtby to move to White Hart Lane as a Bosman free agent at the end of the season. But the injury to Sandro, who has had knee surgery and will miss the rest of the season, has left him short in midfield.

Villas-Boas said after Sunday's 1-1 home draw against Manchester United that it would be difficult to sign Holtby this month, and he noted the German's outstanding performance in Schalke's 5-4 home win over Hanover last Friday. But the Tottenham chairman Daniel Levy has indicated he is now willing to pay a fee for the 22-year-old that suggests an agreement could be reached.

There is the expectation in Germany that Holtby will move to Tottenham this month. Schalke have signed the attacking midfielder Raffael from Dynamo Kyiv and they are close to an agreement for another creative Brazilian midfielder, Michel Bastos, from Lyon.