Arsenal captain Mikel Arteta is a major doubt for their Premier League trip to Swansea City on Saturday.
The Spanish midfielder limped off in the Champions League match with Anderlecht last night, before the Londoners surrendered a three-goal lead to draw 3-3.
Gunners boss Arsene Wenger has attributed Arsenal's collapse to Arteta's withdrawal and now fears that he could be without his skipper for the match at the Liberty Stadium.
Wenger told reporters: "He has done a hamstring. I don't know what is wrong or how long he will be out for."
Arteta will have the international break to recover from the muscle problem ahead of the visit of Manchester United.
