Arsenal centre-back Thomas Vermaelen has been ruled out for at least another month with an Achilles tendon injury.
The 24-year-old has been sidelined since picking up the problem while playing for Belgium in a Euro 2012 qualifier in Turkey on 7 September.
"He is short on fitness and we have to build it up," said Wenger. "It will take three to four weeks and I would rather say late January.
"He has started his recovery and the signs are good."
The Frenchman added that he did not want to take any risks over Vermaelen's injury, which it was initially thought would only keep him out for a week.
"I have been hit so many times with backlash that I am very cautious," said Wenger.
However, there was better news on the recovery of full-back Kieran Gibbs, who has been out for two weeks with an ankle problem but is expected to be fit for the beginning of January according to Wenger.
With goalkeeper Manuel Almunia sidelined until next month with an ankle problem, the Gunners are boosted by keeper Lukasz Fabianski's return to the squad for Monday's Premier League clash with Chelsea at the Emirates.
Midfielder Abou Diaby is also back in the fold after almost two months out with an ankle injury.
Both players would probably have been in the squad for last Saturday's postponed home match with Stoke, as would captain Cesc Fabregas and striker Robin van Persie, who are still building up match fitness following injuries.
"We have everybody back," Wenger told Arsenal TV Online. "We had them in the squad for Stoke: Diaby, Fabregas, Van Persie - Fabianski too.
"They have had one more week to prepare for this game and build up their fitness. That will have helped them of course.
"So, overall we miss only Vermaelen, Almunia and Gibbs now. They will not be back in the short-term - over Christmas - but everybody else is available."
The 24-year-old has been sidelined since picking up the problem while playing for Belgium in a Euro 2012 qualifier in Turkey on 7 September.
"He is short on fitness and we have to build it up," said Wenger. "It will take three to four weeks and I would rather say late January.
"He has started his recovery and the signs are good."
The Frenchman added that he did not want to take any risks over Vermaelen's injury, which it was initially thought would only keep him out for a week.
"I have been hit so many times with backlash that I am very cautious," said Wenger.
However, there was better news on the recovery of full-back Kieran Gibbs, who has been out for two weeks with an ankle problem but is expected to be fit for the beginning of January according to Wenger.
With goalkeeper Manuel Almunia sidelined until next month with an ankle problem, the Gunners are boosted by keeper Lukasz Fabianski's return to the squad for Monday's Premier League clash with Chelsea at the Emirates.
Midfielder Abou Diaby is also back in the fold after almost two months out with an ankle injury.
Both players would probably have been in the squad for last Saturday's postponed home match with Stoke, as would captain Cesc Fabregas and striker Robin van Persie, who are still building up match fitness following injuries.
"We have everybody back," Wenger told Arsenal TV Online. "We had them in the squad for Stoke: Diaby, Fabregas, Van Persie - Fabianski too.
"They have had one more week to prepare for this game and build up their fitness. That will have helped them of course.
"So, overall we miss only Vermaelen, Almunia and Gibbs now. They will not be back in the short-term - over Christmas - but everybody else is available."
