Chelsea’s relatively small squad became exposed further yesterday when Ricardo Carvalho was ruled out for a month because of the knee injury that he suffered only 12 minutes into the 1-1 draw against Manchester United at Stamford Bridge on Sunday. A scan has revealed damage to the medial ligament in the Portugal defender’s left knee, which, although not serious enough to merit surgery, will require rest.

The prognosis for Deco is more encouraging, but the Portugal midfield player is expected to be out for at least a fortnight after pulling a thigh muscle during the warm-up.

Deco has been Chelsea’s outstanding performer in the first month of the season, but Luiz Felipe Scolari, the manager, is likely to find Carvalho’s absence more of a handicap because he lacks quality cover at centre back. Alex replaced Carvalho against United and was relatively untroubled, but the Brazil defender is not an ideal partner for John Terry because both can be exposed by pace.

Other than that, Scolari’s options are limited, with the Brazilian’s lack of faith in Branislav Ivanovic shown by the manager refusing to play him this season. Indeed, the versatile Serb is becoming a figure of curiosity at Stamford Bridge because, nine months after completing a £9 million move from Lokomotiv Moscow, he is still to make his debut.

Carvalho is likely to miss at least three Barclays Premier League matches and two Champions League ties, as well as tomorrow’s Carling Cup third-round visit to Portsmouth, with Chelsea’s medical team concentrating on getting him fit for the home match against Liverpool on October 26. The club are hoping that Deco will be fit to face Aston Villa on October 5, which would enable him to take part in Portugal’s World Cup qualifiers against Sweden and Albania the next week.

Scolari is planning to take a strong team to Fratton Park as he stands by his pre-season pledge of attempting to win an unprecedented quadruple. Scott Sinclair is pushing for his first start of the season and Ivanovic could be handed an overdue debut, but, otherwise, Scolari will pick from the players he has been relying on all season.

Chelsea’s main target is regaining the Premier League title, however, irrespective of Scolari’s claims to the contrary. Salomon Kalou, who scored the equaliser on Sunday, said yesterday that the draw had left them in charge of what he expects to be another two-horse title race.

“If you watch the game again, it’s not a bad result,” Kalou said. “They could even have won, so to come back into the game is a good result. I think it’s good to be in front of Manchester at this stage and at the end of the season it could make all the difference. They’re going to have difficult games and we’re going to have difficult games, but it’s good to be six points ahead. Last year we lost the title by two points, so the important thing is to stay in front of Manchester. As long as we stay in front, we have a chance to win the title.”

Kalou insists that Chelsea are stronger than last season, although Scolari is concerned enough about their strength in depth to add Miniero to his squad in the absence of Michael Essien, who has been sidelined by a serious knee injury. The Brazil midfield player is due in London for a medical and should sign this week.

“We’re stronger now and everyone is fighting for their position,” Kalou said. “We’re trying to be more positive in the team and it’s so difficult to break into the side. This is a good thing for Chelsea and for us because, once you play with great players, you have to give 200 per cent just to get on to the pitch.”