Bendtner, 22, underwent surgery to cure the problem last November but still struggled for fitness when represented Denmark at the recent World Cup in South Africa.
“Bendtner will not be available for the start of the season,” Wenger told reporters after the club's 4-0 win over Neusiedl on Tuesday night.
Wenger also admitted to fears he had over Cesc Fabregas and Robin van Persie with the pair, who lined up against each other in the World Cup final, not due back until August 5.
“Fabregas and van Persie are due to come back on August 5 and from them on we will see how much build-up work is needed physically and as well as how they have recovered mentally for the World Cup.
“They might be short for the first game but I don't know, that will depend on the fitness work they have done during the holiday.”
Defender Johann Djourou gave Wenger another headache in Tuesday's final friendly of their pre-season tour of Austria, picking up a hamstring strain whilst injury-prone Czech midfielder Tomas Rosicky missed the game with a groin complaint.
“Djourou has a small hamstring problem but it is not bad. Rosicky was supposed to play in the first-half but I didn't' want to take the gamble,” the Arsenal boss said.
However, there was better news for Wenger regarding Denilson and Abou Diaby, who both should be available for the Gunners final pre-season friendly with Legia Warsaw on August 7.
“Denison should be fit – maybe not for the Emirates Cup but for the Warsaw game and Diaby as well.”
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