Arsenal boss Arsene Wenger says they'll be stronger with the return of Mathieu Debuchy and Laurent Koscielny.
Debuchy suffered an ankle injury against Manchester City in September but has started to step up his recovery, while Koscielny has been sidelined by a troublesome Achilles problem with no firm return target set.
"We are missing our defensive solidity at the moment, due to injuries," said Wenger, who sanctioned the sale of captain Thomas Vermaelen to Barcelona in August.
"We are paying the price for Debuchy's (injury), because (Calum) Chambers is a central defender.
"I think we have a very good balance between Koscielny and Mertesacker, so we are losing experience at the back at the moment."
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