Arsene Wenger
Wenger is coming under increasing pressure after Arsenal's worst start to a season for 32 years.Getty Images

Arsenal manager Arsene Wenger says Jack Wilshere faces a lengthy spell on the sidelines and will miss the Champions League group match against Borussia Dortmund after limping off against Manchester United.

Wilshere went off after 55 minutes of the Gunners' 2-1 defeat on Saturday after injuring his left ankle following a late challenge from Paddy McNair.

The England midfielder will see a specialist to learn the full extent of the injury but Wenger has confirmed Wilshere will miss the next few Arsenal games including Wednesday night's European clash.

"I cannot tell you a time scale [for Wilshere] but he will be out for a while," said Wenger. "He has to see a specialist next week to see how long he will be out. We don't know for the moment. He has a big ankle strain. We're just told he will be out for the next few games."

Wenger has been handed a further blow with the news that Wojciech Szczesny and Theo Walcott will also miss the game, while Danny Welbeck is a doubt after receiving treatment following the loss to United.

"Welbeck is in the squad after some treatment," the French boss added. "Walcott is out with the same groin problem which he came back from England with and Szczesny is out too. I don't know [where to play Welbeck], I have not decided yet."

However, amid the triple injury blow Arsenal are expected to welcome back defender Laurent Koscielny after the French defender took a full part in training on Tuesday. The France international has been out since November with an achilles injury but is in contention to face Dortmund.

Amid Arsenal's worst start to a season for 32 years, Wenger has come under fire from a number of critics including minority shareholder Alisher Usmanov, who claimed on Monday that the boss had to learn to take criticism.

But while Wenger has refrained from reacting angrily to the comments, he is disappointed the Russian businessman chose to go public with his opinion.

"I think first of all I have shown I can take criticism and everyone has the right to have an opinion," Wenger said. "We have values at this club; we show solidarity and I think that is very important one.

"The second one is that when we have something to say each other we say it face-to-face. I don't take it personally at all. It is an opinion but when you're from this club you're in or out.

"It is not unhelpful but honestly I don't give it a big importance. We know the rules of the game, we know how it works. What matters is how close we are."