Manchester United are preparing potentially to be without Anderson for the next two months after the Brazilian midfielder suffered his second serious knee injury in the space of a year.

Anderson was hurt during the 1-0 defeat of Crawley Town on Saturday, leading to his substitution at half-time, and the disappointing news that he will almost certainly be out of action until the end of April.

The midfielder has damaged medial ligaments and is having further tests to ascertain whether he may need surgery, almost exactly a year since he suffered cruciate ligament damage in a match against West Ham United. On that occasion he was sidelined for seven months.

Since signing from Porto in 2007, Anderson has struggled at times to justify his €30m price tag but his absence still represents a significant setback for Sir Alex Ferguson at a time when he is already light on midfielders going into the first leg of the Champions League tie against Marseille.

Park Ji-sung will also be absent on the flight to France on Tuesday morning, out for three weeks with a hamstring injury, and Antonio Valencia is roughly the same time away from a first-team return after breaking his leg, and there are serious concerns about whether the luckless Owen Hargreaves will ever be in a condition to play for the club again.

Rafael da Silva, the Brazilian full-back, has needed treatment since the Crawley game, and Rio Ferdinand's participation is far from guaranteed after missing the last three matches with a groin injury. Jonny Evans and Michael Owen are also doubts, though neither would have been in the team anyway.