Arsenal will be without midfielder Jack Wilshere, who is set to see a specialist because of an ankle injury, for Wednesday night's Champions League clash against Borussia Dortmund.
Wilshere, who has a history of serious ankle injuries, sustained the latest blow in Saturday's Premier League defeat to Manchester United, when he was forced to limp off after a tackle from United’s Paddy McNair.
Arsenal manager Arsene Wenger said he did not know the exact extent of the injury, but that Wilshere was likely to miss Arsenal’s next few games.
"He has a big ankle sprain," Wenger told a news conference at Arsenal's training ground.
"I don't want to say how bad it is because I'm not a specialist medically. The first news is that he will be out for the next few games.
"To know how long he will need to see a specialist."
Forward Theo Walcott (groin) also misses out, along with goalkeeper Wojciech Szczesny, who injured his hip during Saturday's Premier League defeat to Manchester United, but striker Danny Welbeck (knee) is expected to be available and defender Laurent Koscielny is in contention again following an Achilles problem.
Striker Olivier Giroud, fit again from three months out with a broken leg, was not registered for European competition.
Mesut Ozil (knee), Mathieu Debuchy (ankle), goalkeeper David Ospina (thigh) and Abou Diaby (calf) are all still unavailable.
Arsenal can clinch a place in the last 16 of the Champions League providing they avoid defeat against Dortmund in their final home game in Group D.
