Andre Villas-Boas has warned Chelsea fans they may have to wait until after the international break to see Juan Mata in action for the club.

Wednesday night saw the Blues complete the signing of World Cup winner Mata, who is expected to add some much-needed creativity to its midfield.

Manager Villas-Boas has revealed the 23-year-old, for whom Chelsea reportedly paid Valencia around £24million, is unlikely to start Saturday's Premier League game against Norwich, although he could well be on the bench.

"This league is very, very specific in terms of intensity, emotionally and culturally," Villas-Boas said.

"It doesn't mean he's not threatening the starting XI, but two training sessions is short for a player creating new relationships with the players.

"Friday is a decisive day in terms of the strategic part of our game, so that's when we'll decide."

Villas-Boas has repeatedly insisted he is happy at the quality of the squad he inherited from predecessor Carlo Ancelotti, but the arrival of Mata and his pursuit of Luka Modric and Alvaro Pereira suggests otherwise.

He added of Mata: "We were looking for a player that gives us some creativity in the final third.

"Not that we don't have that, but you always want to add it when you can find talent of this nature.

"The price was reasonable for his qualities and what he's shown in the Spanish and Champions League.

"He's an addition that everybody was looking forward to.

"He has an eye for goal and a magnificent record for assists throughout his career since joining Valencia from Real Madrid B."

Arsenal failed in a bid to land Mata before Chelsea pounced, and Villas-Boas revealed he too came close to missing out on the Spain star.

"It was difficult in the beginning of the negotiations with Valencia," he said,

"For them, he was one of their biggest assets and they weren't very open to talk.

"We lost a couple of days in that situation while we were colliding, but that was okay."

Villas-Boas faces even tougher negotiations if he wants to land Modric and Pereira before the transfer window closes on Wednesday.

It has been suggested Chelsea is considering testing Tottenham's resolve to keep hold of Modric by offering them up to £40million.

Chelsea is also deciding whether to increase their reported £16.6million bid for Porto wing-back Pereira, who has a £26million release clause which is highly unlikely to be met.

In addition, reports in Italy suggest Chelsea may consider a deal that would see them sign Juventus' Milos Krasic, with Alex moving in the opposite direction.

Alex had a less-than stellar game against West Brom last weekend and could find himself replaced in the heart of Chelsea's defence by the fit-again Branislav Ivanovic on Saturday.

The game comes too soon for David Luiz, who will complete his recovery from a thigh injury on international duty with Brazil next week.

"It'll be too early for him, but I'm going to let him go with Brazil to get some minutes," said Villas-Boas, who revealed goalkeeper Petr Cech could also return from his knee injury sooner than expected.

"Petr has made a tremendous recovery and it's looking good for after the international break."

Villas-Boas admitted Saturday's opponent is something of a wildcard.

"I can only assess them from the first three games this season," he said of Paul Lambert's Canaries, who was runners-up in last season's Championship.

"There were some changes that Paul made in those matches, so that leaves us trying to find out what he's going to do.

"To get the starting XI right would be difficult for us. He's changed the team dramatically."

He added of Lambert, who won the Champions League with Borussia Dortmund as a player: "I look forward to playing against him.

"He has his experiences in European football, which is why he maybe defends this mixture of European flair and solid organisation."

Lambert will be without defender Daniel Ayala, who is set to miss up to eight weeks with a knee injury.

Canaries' Playmaker Wes Hoolahan (hamstring) will be monitored, centre-back Leon Barnett returns after a one-match ban, as Lambert is set to make changes from the side thrashed 4-0 at home in the Carling Cup on Tuesday night.

Striker James Vaughan and centre-half Elliott Ward are still sidelined after picking up minor knee injuries during pre-season.

Teams:

Chelsea (from): Hilario, Ivanovic, Bosingwa, Ferreira, Terry, Alex, Cole, Mikel, Romeu, McEachran, Lampard, Ramires, Benayoun, Mata, Malouda, Torres, Drogba, Anelka, Kalou, Lukaku, Turnbull.

Norwich (from): Ruddy, Tierney, Barnett, de Laet, Naughton, Bennett, Johnson, Fox, Crofts, Pilkington, Holt, Rudd, Martin, Whitbread, Hoolahan, Surman, Jackson, Morison.