Oxlade-Chamberlain is one of several players who picked up injuries in Saturday's 3-1 home defeat to Aston Villa, leaving manager Arsene Wenger with a selection headache for Wednesday's crucial Champions League qualifier against Fenerbache.
Wenger was waiting on the results of a second scan on Oxlade-Chamberlain after the England international left the Emirates Stadium on crutches on Saturday.
Oxlade-Chamberlain, 20, was involved in a nasty collision with Aston Villa defender Antonio Luna and Wenger admitted: “He is out, definitely out (for the Fenerbache trip). It's a knee problem. It's a bad injury.”
Thomas Vermaelen, Nacho Monreal, Mikel Arteta and Abou Diaby were already confirmed to miss the the midweek clash through injury. Sagna, who will continue to be assessed ahead of the trip to Turkey, is Wenger's biggest doubt after falling awkwardly on his neck against Villa.