ANDRE Villas-Boas admits Gylfi Sigurdsson is struggling to rediscover the form he showed at Swansea City last season.
But the Spurs boss insisted the club had no choice but to reject Reading's megamoney bid to sign the former Liberty loan star before the transfer window closed.
The Royals are rumoured to have offered around £10 million for the attacking midfielder, who has made little impact at White Hart Lane this season.
"He's a player that we rate very highly," said Villas-Boas. "We brought him here after his amazing contribution for Swansea last year and he's a player that we have high expectations for. "Probably this season is not going to the level that he wants at the moment, but obviously the step is much more difficult than it was at Swansea. He's a player that we believe a lot in, and in his future here. We couldn't let him leave."