The 34-year-old will go straight into the squad for Monday's FA Cup third-round clash against Leeds at the start of a six-and-a-half-week spell which will take in games against Manchester United, AC Milan and possibly the visit of Tottenham on February 26.
Nevertheless, Arsenal boss Wenger feels throwing Henry straight back into action would perhaps be a step too far.
"Thierry will be involved against Leeds, but at the moment 90 minutes is a bit long for him because he has not played for a long time," Wenger said.
"He works hard, but he is a bit behind physically. In one or two weeks Thierry will be fine."
Henry became Arsenal's record goalscorer during eight trophy-laden seasons before leaving to join Barcelona in 2007.
Only last month, the Gunners unveiled a bronze statue of Henry outside the gates of the Emirates Stadium as part of their 125th anniversary celebrations.
Wenger believes Henry's return can only be good for all involved.
He said: "You cannot take away from people what they have done, and what he has delivered will stay forever. It can just make the statue a bit bigger. Let us hope he will do that.
"Thierry is a world-class player and even at this club a player of that dimension is always very difficult to find, especially at this period of the season.
"He can just add something more to the team."
Henry admitted he never expected to return to Arsenal, but when the opportunity presented itself he could not turn it down.
However, the World Cup winner is conscious of how he has changed as a player.
"I am not 25 any more, I am not going to take the ball from the middle of the park and dribble past five or six players. Don't expect that," said Henry, who will link up again with New York Red Bulls ahead of the start of the Major League Soccer season in March.
Arsenal will be without Gervinho on Monday night as he heads off to link up with the Ivory Coast ahead of the African Nations Cup.
While the Gunners successfully lobbied Morocco to delay the departure of striker Marouane Chamakh, Wenger did not want to use his relationship with Elephants coach Francois Zahoui to try to sway things over Gervinho.
"I do not want to go to war with him. He would be in a difficult position," said Wenger, who was Zahoui's manager at Nancy.
"If I keep Gervinho for Monday and Yaya Toure and Kolo Toure have to go [from Manchester City] on Sunday, it would be unfair."
With Gervinho away, Theo Walcott will be expected to provide the service to Henry and in-form captain Robin van Persie, who will be rested against Leeds.
Wenger insists he is happy with Walcott's form, with the England winger often criticised for inconsistent displays and linked with a move to Juventus amid reports of contract issues.
"We want to keep Theo and he knows that. Of course [he earns his money], he works every day and works very hard," Wenger said.
"His attitude is great, I have no problems with that at all."