The 34-year-old former Gunners captain will go straight into the squad for Monday night’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 even the visit of Tottenham on February 26.
Henry became Arsenal’s record goalscorer during eight trophy-laden seasons with the north-London club before leaving to join Barcelona in 2007.
Only last month, the club unveiled a bronze statue outside the gates of Emirates Stadium to Henry 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.
“Who would turn down a player of his quality? We have a good spirit in the side and he will add something more, experience-wise, and on the nervy side as well, when we are under pressure.”
Wenger is in no doubt Henry still has the quality to compete at the highest level, the striker having trained at his old club since the end of the Major League Soccer season, where Red Bulls were knocked out of the play-offs by David Beckham’s Los Angeles Galaxy.
The Arsenal manager said: “Thierry is like everyone who develops in life, he is more open to people. When you are a young striker you are more focused on yourself and today, what he can give to others is of a higher level than he could do five or six years ago.
“Thierry is in a position where has done it all and is under less pressure than five or six years ago.
“We want him to perform. I want him to help the team and do well. I don’t even have to say a word because he will want to do that himself.”
Henry admitted he never expected to return to Arsenal, but when the opportunity presented itself he could not turn it down. He said: “It did happen pretty fast but when it comes down to Arsenal it is pretty hard for me to say no.
Henry, though, is conscious of how he has changed as a player. He added: “I am not 25 anymore, 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.”
Arsenal’s Barclays Premier League ambitions took a knock with defeat at Fulham, where they lost 2-1 in stoppage time after having defender Johan Djourou sent off when they were in front.
However, Wenger expects a response from his injury-hit squad. He said: “The schedule was very tough for us and I feel as well we were really unlucky over the Christmas period.
“I cannot fault the players’ attitude or spirit and that’s why I’m still optimistic. We must come back even stronger.”