One notable absentee from the squad for victory over Champions League opponents Olympiakos was German centre-back Mertesacker, who assistant coach Steve Bould revealed is the latest Arsenal player to be struck down by illness.
"He was ill this morning," the former defender said. "He has a bit of a virus I believe so that's where he is at. We're hoping he is fit for the weekend.
"I am told it is a different virus each time so I don't know if its in-house, I've got no idea.
"We've had about four of them ill over the period of about two weeks."