Thierry Henry will miss Arsenal's trip to Hamburg after he suffered a reaction to a recent foot injury.
The Arsenal captain had picked up the problem while on international duty with France in the Euro 2008 qualifier against Italy last week, but he played through the pain barrier to face Middlesbrough on Saturday.
However Henry expressed concern following training at London Colney this morning and it was decided the striker should not be involved in the Champions League tomorrow.
Wenger, though, has already made do without his talisman once in Europe this season, as Arsenal came through the opening leg of the Champions League qualifier 3-0 away to Croatia Zagreb.
Robin van Persie and Emmanuel Adebayor are again likely to lead the attack, with England Under-21 forward Theo Walcott and new signing Julio Baptista other options from the bench.
Wenger revealed to reporters at Luton Airport this afternoon: 'Thierry is not playing. He had a foot injury which he got against Italy.
'We injected him on Saturday, but he has had a reaction on it.
'We tried it again this morning, but he was not ready.
'It is a short-term thing. He should be okay for Manchester United on Sunday, but the doctor said he was not fit enough to play tomorrow.'
The Arsenal manager added: 'We have a big squad, a strong squad and in the short term it should be no problem.
'We will deal with it.
'We have already played without him and won in the Champions League this season.'
Wenger has not been best pleased to see so many of his squad away on international duty so soon after their return from the World Cup.
The Arsenal manager reflected: 'I think his injury was down to his disturbed pre-season, but we hope he will get better.
'I can accept it, but what is more difficult to accept is the international calendar because that is where the clubs suffer.'
Wenger rested Walcott for the weekend Premiership 1-1 draw with Middlesbrough.
The Arsenal manager is wary of burning out the 17-year-old, who has impressed when coming off the bench.
Wenger said: 'I left Theo out on Saturday because it was a very physical game and he has had problems to finish a game.
'He is a bit behind physically, but I do not know whether he will be ready to start.
'If I play with wingers he might play, but we will see.
'Baptista is also a little bit behind.'
Wenger's side have yet to win in the Premiership, drawing two and losing one of their first three matches - the worst start to a top-flight campaign under the Frenchman.
While fully expecting to build on last season's brilliant run to the European Cup final, Wenger acknowledged: 'We want to do well in the Champions League, but the Premiership means a lot to us this season as well.
'I feel this team is one of the strongest squads I have ever had.'
Wenger added: 'But we need a bit of patience, keeping our nerves and find the right balance in our attacking and defending because we look strong everywhere, but we are making it difficult for ourselves in every game.'
Wenger, however, insisted there was no question of sacrificing a result in the AOL Arena tomorrow for one against United this weekend.
The Arsenal boss declared: 'We do not trade. We want to win every game.
'It is not buy and sell, you want quickly to win.
'To win tomorrow will give us a stronger chance to do well at Old Trafford.'
Arsenal, meanwhile, will play in their yellow change strip tomorrow night.
Hamburg are also sponsored by Emirates, and under UEFA regulations, no two teams playing each other can display the same corporate logo.
So instead, the Gunners will have 'Dubai' on their shirts.
Chairman & chief executive of Emirates Airline & Group, Sheikh Ahmed bin Saeed Al Maktoum said: 'Luck played its part in bringing both our sponsored teams together in the draw, and we worked closely with UEFA to enable us to maximise our promotional exposure without contravening Champions League regulations.
'Dubai and Emirates are intrinsically linked, and this unique promotional opportunity will once again communicate this message to a global audience.' The shirt arrangement will be reversed during the return leg of the Group G encounter in November.