"He has an inflamed ankle, the other ankle to the one he injured [before]," Gunners boss Arsene Wenger said.
"He has some bone bruising. The last time it deteriorated into a stress fracture. That's what we don't want to happen.
"We trust people who are specialists in this area.
"He was out for 17 months and we had to deal with it. We must be able to deal with it for two or three games."