Arsenal boss Arsene Wenger has confirmed William Gallas will miss the rest of the season with a medial knee ligament injury.
Gallas was forced off with the problem in the first half of Arsenal's 1-1 draw with Villarreal in their UEFA Champions League quarter-final on Tuesday.
The Frenchman picked up the knock after colliding with Villarreal striker Giuseppe Rossi.
Wenger feared after the match that Gallas had sustained a serious injury and his worst worries have been confirmed, with the centre-back facing several weeks on the sidelines.
Goalkeeper Manuel Almunia also faces a spell out of action after suffering an ankle injury in midweek.
The Spaniard was forced off after he was also, coincidentally, caught by Rossi in the first half.
It means Polish keeper Lukasz Fabianski will have an extended run in the side, starting with this weekend's clash with Wigan.
Full-back Gael Clichy has also been ruled out of the trip to Wigan and the second leg against Villarreal after picking up a back problem in Spain.
"We have not the best news for Gallas because he looks to have a medial knee ligament that takes him out," said Wenger.
"He is quick to recover, but we think he will be short to come back before the end of the season.
"It's a big, big blow but that's where the squad comes in.
"I believe as well we have lost Manuel Almunia for three weeks and we lost Clichy for two weeks with a back problem.
"We lost three players on Tuesday night so we have to once again rely on the depth in the squad - that is quite strong but as well we have to rely on our mental strength because until now we have dealt well with all our injury problems."
Wenger also revealed Robin van Persie and Eduardo, who both missed Tuesday's match, are struggling to be fit for Saturday and will undergo fitness tests before the game.
"Robin van Persie and Eduardo will have tests on Friday morning. They could be available," added Wenger.
Wenger admitted injury-plagued star Tomas Rosicky had suffered a setback in his bid to return to action.
Rosicky has not played since last January and Wenger concedes the midfielder is no closer to making his long awaited comeback.
Wenger said: "Tomas Rosicky, at the moment, is not close to coming back. We have to be very patient there as well. But of course we have (Andrey) Arshavin available for Saturday again."