The England international sustained a torn cruciate ligament in an FA Cup tie with Tottenham last January, missing the latter half of the 2013-14 season and the World Cup as a result.
Walcott has made two substitute appearances this term, against Burnley and Swansea in November, and returned to the bench at Liverpool at the weekend after suffering a minor groin injury.
Wenger confirmed that Walcott is "not far" from making his XI over the busy festive period, and the Frenchman is confident his attacker will not miss a step when he does return.
"He has been missed because first of all he's a top quality player," Wenger said.
"He's a team player as well when he got injured he was in top form too."
When asked if Walcott would return to top form, Wenger added: "I think so because Theo was born 1989, 25 years old it's the best age now for a player of his quality.
"He's as quick as he was believe me, I see it in training."
Arsenal have played the first half of the season with just six senior defenders in their squad, resulting in full-backs Nacho Monreal and Mathieu Debuchy featuring in previously untested central roles.
Highly rated Ipswich Town defender Tyrone Mings has been heavily linked with a move to the Emirates Stadium, but Wenger brushed off questions regarding the 21-year-old, signed from Chippenham Town for £10,000 in January 2013.
Wenger said: "The intensity of the link is not down to us."
