Unai Emery would like Arsenal to add a center-back during the January transfer window.

Arsenal are facing a shortage of defenders after Rob Holding was ruled out for the season last week with a torn knee ligament, while Laurent Koscielny is only now ready to play his first game of the campaign after recovering from an Achilles injury.

"If we can take one player to help us at center-back, I think it's a good option," Emery said. "But a transfer is not easy."

Manchester United's Eric Bailly and Chelsea's Gary Cahill have been identified as options.