Arsene Wenger has suffered a double injury blow as he discovered Gael Clichy will be sidelined for two weeks with a back injury and William Gallas's knee problem will keep him out for the rest of the season.

Gallas left Estadio El Madrigal on crutches after limping off midway through Tuesday night's 1-1 draw with Villarreal in the first leg of their Champions League quarter-final.

Scans have revealed the Frenchman has a similar problem to that which ruled captain Cesc Fabregas out for nearly four months.

With a busy schedule coming up, including Saturday's trip to Wigan, next week's return leg in Europe and an FA Cup semi-final at Wembley against Chelsea, Wenger's squad will once again be tested to the limit.

As well as Gallas and Clichy, goalkeeper Manuel Almunia is also out for three weeks with an ankle problem. But manager Wenger insists he has the required strength in depth to cope.

“William is a quick recoverer but we think he'll struggle to come back before the end of the season,” said Wenger.

“It's a big blow. We lost three players on Tuesday night so we have to once again rely on the depth of our squad. Until now we have dealt well with all our injury problems. Robin van Persie and Eduardo will have tests tomorrow morning and they might be available.”

Arsenal potentially face a run of six games in 18 days should they reach the Champions League semi-finals and Wenger added: “Fatigue is something you don't want to talk about.

“The experience I had in France is that when you always talk about fatigue you end up getting tired. It can happen, the mysterious nature means that a team can look flat as a unit.

“I haven't decided yet if I will rest players on Saturday but we may rotate because offensively we have many solutions.”