Ferdinand injury 'not improving'

Ferdinand's absence is frustrating Man Utd manager Sir Alex Ferguson

Manchester United's Rio Ferdinand faces a prolonged injury absence as the club try to find the cause of his problems.

The defender is out of Sunday's match at Chelsea with a calf injury, which manager Sir Alex Ferguson fears is related to a lower back problem.

"There has been no improvement," said Ferguson. "We are having to look at something different.

The injury is likely to rule Ferdinand out of England's friendly against Brazil in Qatar next week.

"Usually you are back from a calf injury within two or three weeks," added Ferguson.

"But there is no sign of recovery from this injury so we are looking at whether it is to do with his lower back."

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Ferdinand, who missed the first month of the season after tearing a thigh muscle in training, has struggled with form this season, not helped by a nagging calf injury.

His last appearance was in the 2-0 defeat by Liverpool at Anfield, Ferdinand who turns 31 on Saturday, has missed Manchester United's last three games.

Fellow centre-back Nemanja Vidic has a niggling calf injury but is expected to face Chelsea in the top-of-the-table clash at Stamford Bridge.

Meanwhile, Ferguson has praised Chelsea boss Carlo Ancelotti, saying he is not surprised by the Italian's impressive start in English football.

"I thought Ancelotti would do well," said Ferguson.

"He was a great coach at AC Milan. He won the European Cup twice and brought a wealth of experience with him to Chelsea.

"He was also a great player so he has a lot of knowledge. He brought a different system to the ones Chelsea have used in the past.

"It has maybe been easier to adapt tactics because they have very experienced players, who have more tactical knowledge than the younger ones."

Chelsea go into Sunday's top-two clash with a two-point advantage and United have not won at Stamford Bridge since 2002.

"We have to get our act together because our record down there has not been good for the last six years," added Ferguson.

"It is a strange situation because we used to have a terrific record down there up until a few years ago. But we have let it slip.

"The players all realise it is going to be a big game and their performance is going to be important."