The 25-year-old has been a big hit in his first season with the Gunners, but will now miss several weeks of the crucial title run-in.

Manager Arsene Wenger confirmed: "He has an ankle injury and the first news that we have is that he could be out for quite a while.

"I don't know exactly how long he will be out, but I feel it will be three weeks at least. Five is the worst-case scenario.

"I have seen the injury again on tape. He wanted to kick the ball out and he twisted his ankle, that made it a bad injury.

"It is a big blow because he has been a revelation for us, a fantastic player."

Meanwhile, Wenger has backed his side to recover from a run of five games without a win which has seen their title hopes fade dramatically.

He added: "What we want to do is perform well as a team again and we know we can do that.

"Recently what punished us a lot is that defensively we have made big mistakes.

"We are going through a bad patch, but we want to come back and win the games again that we can win."