Both Chelsea and Manchester United expect a fiercely competitive Premier League match when they meet at Stamford Bridge on Sunday.

MANCHESTER, ENGLAND (NOVEMBER 6, 2009) ITN - The scene is set for a typically robust Premier League tussle when champions Manchester United visit competition leaders Chelsea on Sunday. (November 6)
Both teams expect a fierce battle with the Blues beginning the match four point clear of their main title rivals.

Manchester United defender Rio Ferdinand, whose form for club and country has been under close scrutiny this season, will miss the match at Stamford Bridge amid growing fears over his fitness.

United manager Alex Ferguson, who marked his 23rd anniversary in charge of the club on Friday, said that experts have been unable to pinpoint the nature of a calf injury which has sidelined the defender for the last two weeks.

"We don't know exactly where the calf injury is coming from," Ferguson told a news conference. "Whether it is coming from the lower back, whether it is a nerve thing.

"But calf injuries are normally two to three weeks and he is showing no sign of recovering from that injury so we're looking at the whole situation."

Ferdinand, who turns 31 on Saturday, has had his form widely questioned after indifferent performances for United and Fabio Capello's England team so far this season and the potential for an extended spell on the sidelines constitutes a major setback.

Serbian defender Nemanja Vidic has been passed fit for the clash with Chelsea, along with midfielder Darren Fletcher who has recovered from a minor injury collected in the midweek Champions League draw against CSKA Moscow.

Ferguson, 67, would like nothing more than to mark his anniversary at Old Trafford with a rare victory at Stamford Bridge, his club having failed to win there in the last seven visits. Chelsea top the standings on 27 points from 11 matches, two ahead of second-placed United.

"There's no point looking back six years," Ferguson added.

"It's looking at the present team and what they're capable of and they're capable of winning the game, I don't think there's any doubt about that. It's not going to be an easy game for either team. It's going to be a tough match. At moments it'll be intense, fiesty, but there are so many good players on the pitch, you're expecting some moments of terrific play and I think we'll get that on Sunday."

Chelsea top the standings on 27 points from 11 matches, two ahead of second-placed United. Ferguson is not surprised Blues mangaer Carlo Ancelloti has made a strong start to his tenure in charge.

"Ancelotti was a great coach at AC Milan, he brings a wealth of experience," Ferguson said.

"He's won a European Cup twice, he was a great player also so he's got a wealth of knowledge. I thought he'd do well. I think what he's changed is that he's brought a different system to Chelsea what has been using in the past and it seems to have done well."

Meanwhile Chelsea have been cleared to sign new players in the January transfer window after the Court of Arbitration for Sport (CAS) suspended a ban imposed by world body FIFA.

The English Premier League leaders had asked for a stay until the result of an appeal was decided.

The court said in a statement that they had granted the request, with the sanctions suspended "until the CAS renders its final decision in this matter." No date was given for the decision.

Chelsea were banned from registering any new players, nationally or internationally, until January 2011 after being found guilty in September of inducing Gael Kakuta to break his contract with French club Racing Lens.

The punishment was handed out following a contractual dispute involving the transfer of reserve team player Kakuta, now 18, from Lens in 2007.

Chelsea manager Carlo Ancelotti said now was not the time to be thinking about signing players in January despite the CAS appeal decision.

"We have this possibility now but we have time. We don't want to make a decision at this moment. I am very happy about this squad, these players and it's not neccessary in this moment to take players," he said.

Ancelotti is more focused on United and believes this weekend is the perfect time for Chelsea to play them.

"We are happy to play this game at this moment because we are playing very well, we are in good condition and we have a very good mental attitude just now," he said.

Chelsea have only one player unavailable for the match, defender Jose Bosingwa. Ancelotti said the decision about whether the Portugal back would need an operation on his knee injury would be made in the next few days.