Vermaelen out until New Year
The Belgium centre-back has not played since damaging his Achilles on international duty against Turkey in September.
He was not expected to be out for more than a week at the time, but three months on Wenger said there was still no definite return date.
"Vermaelen is in a (protective) boot," Wenger said on the club website. "We want him back and I hope he will be back soon, but not before January."
Arsenal are top of the Premier League but have conceded nine goals in their last six games in all competitions prompting questions about their defensive solidity.