Arsenal defender Andre Santos faces a spell on the sidelines after he was injured in Tuesday's defeat at Olympiakos.
The Brazilian suffered an ankle injury during the second half of Arsenal's 3-1 UEFA Champions League defeat in Greece.
Santos was one of just two starters from the weekend to make the trip to Greece despite being Arsene Wenger's only fit senior left-back.
The injury to Santos leaves Wenger with a selection headache as Kieran Gibbs is still recovering from a stomach problem.
"Santos suffered a bad ankle injury. He looks like he will be out for a while," admitted Wenger.
"We have Kieran Gibbs coming back (from a stomach problem) in two to three weeks. Hopefully Santos will not be too long but, for Saturday against Everton, he looks to be short."
Lukasz Fabianski could also face a spell out of action after being stretchered off against Olympiakos following a clash with Gunners team-mate Thomas Vermaelen
"He felt a deep cut on the knee," Wenger said of Fabianski.