The manager says the midfielder is in the best shape he has been in for three years, despite the recent pictures of him smoking while on holiday, ahead of an "important" campaign
Wenger's side face Benfica and Monaco as part of the Emirates Cup at the weekend as they prepare for their Premier League opener against Crystal Palace on August 16.
Wilshere suffered an injury-interrupted campaign last season before enduring a disappointing World Cup with England and was pictured smoking during the summer.
The 22-year-old has since apologised for the incident on holiday, insisting it was a mistake, and Wenger insists the England international is in top shape.
"It's a big season for Jack but he's in the best shape he's been for three years," he told reporters.
"He has prepared and has got over his ankle problems, I think he will have a great season but it's a very important season for him."
Before the Premier League kicks off Arsenal face Manchester City in the Community Shield and Wenger feels the Emirates Cup will be important for his side’s fitness levels ahead of the Wembley clash.
"It's a real test ahead of the Charity Shield and the Premier League, as well as Champions League qualifier," he added.
"I'm more interested in the fitness because we have a stable team and know the football we play.
"We have a short time available but I'm quite happy with where we are. I will tell you more on Monday."