Arsene Wenger admits Samir Nasri is now a major doubt for their Champions League clash against Barcelona after his FA Cup gamble "backfired".
Influential midfielder Nasri picked up a hamstring injury in the 2-1 FA Cup fourth-round win over League One Huddersfield at The Emirates on Sunday.
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.
However, 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.
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.
However, French playmaker Nasri then limped off with a hamstring problem as he chased a long kick up field from Manuel Almunia.