André Villas-Boas has attempted to bring forward the signing of Lewis Holtby from Schalke to this month's transfer window after losing the key midfielder Sandro to a long-term knee injury.

The Tottenham Hotspur manager has agreed a deal for Holtby, the highly rated attacking midfielder, to move to White Hart Lane at the end of the season as a free agent; Holtby has signed a pre-contract to that effect.

But the loss of Sandro to surgery has prompted Villas-Boas to explore his options, which have also included telling Tom Huddlestone that he does not want to lose the 26-year-old this month. Schalke are believed to be open to the cut-price sale of Holtby this month as that would at least grant them a fee.

Huddlestone has grown frustrated at his lack of regular opportunity in Tottenham's starting Premier League team and, with Scott Parker, another midfielder, back to fitness after a foot problem, he has been considering Fulham's interest in him.

The Fulham manager, Martin Jol, signed Huddlestone from Derby County when he was in charge at White Hart Lane and has made him his priority target. Jol is keen to add creativity to his midfield and discussions between the clubs have taken place. Fulham's interest in Huddlestone dates back to Roy Hodgson's time as manager at Craven Cottage.

Sandro's injury, however, has made it impossible for Villas-Boas, the Tottenham manager, to consider parting with Huddlestone. Sandro landed awkwardly during Saturday's 0-0 draw at Queens Park Rangers and departed in obvious pain before scans confirmed his worst fears.

Tottenham have said that the Brazilian, who went straight from his nation's Olympic Games campaign into the Premier League season, has undergone the operation and that a rehabilitation programme would be mapped out for him. It is feared that he will not play again this season.

Sandro's injury has also had an impact on another Tottenham midfielder, Jake Livermore. The 23-year-old had hoped to sign on loan for QPR earlier this week, after a deal had appeared to be in place last Friday. But he remains at White Hart Lane for the time being, even if Harry Redknapp, the QPR manager, still hopes to force through the loan for the remainder of the season. Fulham are also interested in a loan for Livermore.