Arsene Wenger admits Samir Nasri is now a major doubt for Arsenal's Champions League clash against Barcelona after his gamble "backfired" when the influential midfielder sustained a hamstring injury in Sunday's 2-1 FA Cup fourth-round victory over npower League One Huddersfield at Emirates Stadium.
Because of concerns over the fitness of Tomas Rosicky, who has been troubled by a virus, Wenger elected to put Nasri in the starting XI, but French playmaker Nasri then limped off with a hamstring problem as he chased a long kick up field from Manuel Almunia.
Wenger said: "Nasri looks to have a serious hamstring injury. I have now regrets because the plan was to play Rosicky, but he was still too weak because he was sick, so I took the gamble on Nasri. It backfired, but he could have come on and that happened as well. It is very difficult to predict."
He added: "Usually it is three weeks. We have to see. If it is a grade 1, it will be two weeks, so we will see.
"We are at the stage of the season where we play so many games that to lose bodies is very difficult for us. But Samir is a big blow."
The Gunners made sweeping changes from the side which had booked a place at Wembley with their midweek Carling Cup semi-final second leg win over Ipswich.
It had all been going to plan when Nicklas Bendtner's angled shot deflected in off Terriers skipper Peter Clarke to put the Gunners ahead on 22 minutes.
Sebastien Squillaci was shown a red card by referee Mark Clattenburg for blocking Jack Hunt's surging run just before half-time.
Alan Lee headed a deserved equaliser for the Terriers, but captain Cesc Fabregas came off the bench and won it from the spot after Jamie McCombe was adjudged to have pushed Bendtner over.
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