Jack Wilshere will see a specialist to assess his ankle injury, Arsenal manager Arsene Wenger has announced.
Wenger confirmed that Wilshere would be "out for a while" after coming off during the 2-1 defeat by Manchester United on Saturday after feeling some discomfort.
Wilshere, who was replaced by Santi Cazorla in the 55th minute of the game at the Emirates Stadium, will therefore miss the Champions League clash with Borussia Dortmund on Wednesday.
Wenger did confirm, however, that Laurent Koscielny is back in the squad following an Achilles problem and Danny Welbeck is expected to be included, although striker Olivier Giroud is not registered and Theo Walcott is still ruled out.
Arsenal's injury list
Arsenal's injury list
1/5 Mikel Arteta (midfield)
Like Diaby, the Spaniard is closing in on a return but the Swansea match will come to soon. The club captain last played in November.
2/5 Mathieu Debuchy (defender)
Returned in the FA Cup semi-final win over Reading but has since been ruled out with injury and Wenger confirmed he remains 'unavailable'.
3/5 Alex Oxlade-Chamberlain (midfield)
Suffered a hamstring injury against Manchester United in the FA Cup and hasn't played since as it has exacerbated a groin problem. Out at least until May and facing surgery in the summer.
4/5 Aaron Ramsey (midfield)
Aaron Ramsey caught a kick on his calf during the win over Hull and was later substituted. The Welshman was rated 50/50 for the Swansea match by Wenger, but it now appears that he is a major doubt for the clash at the Emirates.
5/5 Danny Welbeck (forward)
Danny Welbeck has not played since the goalless draw with Chelsea towards the end of April after suffering a knee injury. Wenger has confirmed that the injury is 'nothing major', and that he should return to full fitness before the end of the season.
Wenger admitted concern over Wilshere's injury, although X-rays after Saturday's match indicated there was no bone break.
"I cannot give you any time schedule there because he will be out for a while and he has to see a specialist next week to see how long he will be out. We don't know at the moment," said Wenger at Tuesday afternoon's press conference.
"He has a big ankle sprain and I don't want to talk about it because I am not a specialist medically.
"The first news is they have told us that he will be out for the next few games. [To find out] for how long, we will need to see a specialist."
Wenger, though, believes the return of France international Koscielny will boost the Gunners' rearguard, which was brutally exposed by United on the break.
"He's in the squad for tomorrow. It's very good news because he was out for a while now and we are short in numbers defensively. It's good to have his quality back," said Wenger.
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