Ricardo Carvalho, the Chelsea defender, could be out for up to a month after injuring a knee in Sunday’s Barclays Premier League match with Manchester United.

The 30-year-old suffered medial collateral ligament damage during the 1-1 draw and was taken off in the 12th minute of the clash at Stamford Bridge, with medical staff estimating the problem will lead to between three and four weeks on the sidelines.

Fellow Portugal international Deco also sustained a tear in his thigh during the warm-up and will be out for a fortnight.

The blow of losing Deco, however, will be softened by the imminent arrival of Mineiro, the Brazil midfielder, as a free agent. The 33-year-old will provide cover for John Obi Mikel in a holding role, with Michael Essien already out for six months.

Despite a solid performance from Alex after coming off the bench against United, it is Carvalho’s loss that could be most significant for Luiz Felipe Scolari, the manager, such is the formidable partnership he has formed at the centre of the Chelsea defence with John Terry, the England captain.

“He [Carvalho] is a player that is very fast and he smells when the ball is coming,” said Scolari last week. “He can read where the ball is going to be and go.”

The former Porto defender could return after the next international break and could make the Champions League tie against Roma or the Premier League clash against Liverpool if he is sidelined for the full month.