Wenger's Friday press conference was dominated by talk of Wilshere and he absolved Liverpool defender Daniel Agger of blame for the tackle which caused the small fracture of the midfielder's foot.
Wilshere faces a race against time to play again in the Premier League this season and the injury could even see his England World Cup place under threat, with Wenger admitting he needed to get away from the club and focus on something else for a while.
Wenger said: "I believe it (the tackle) was accidental. Jack will be out for six weeks. The tackle was strong but I think he wanted to go for the ball.
"It is a blow for Jack and for us, from now on we want to get him to recover and come back as quickly as possible and prepare for the rest of the season.
"You can only be very down in this situation, especially in the first days. He is in a boot and has gone away for a few days to get away from things and think about something else.
"It's certainly very difficult and at his age you want to play. You get up in the morning, jump out of bed and get on the football pitch and play. When you are not capable of doing that without any restriction it is difficult mentally. It is a weight on his mind and I hope that it is his last accident for a long, long time."
Wenger moved to allay any fears Wilshere would not feature again for Arsenal this season.
"Yes (I expect him to). There are 11 weeks to go, he will be out for six before he can absorb normal training," said Wenger.
"The maximum after six weeks I think before being competitive in a game, because he will work on his fitness during his injury, is two weeks, so it is eight weeks (to be back playing again)."
Wilshere played on following treatment until he was replaced on the hour, and afterwards maintained it was "just a bruise" when he spoke to reporters, having been initially assessed by the Football Association.
A scan at Wembley failed to show the fracture and it was only when Arsenal, via an independent radiologist, conducted a more detailed test of the injured area that the real problem became more apparent.
The FA now faces an insurance bill which could be as high as £600,000 to cover Wilshere's absence from Premier League duty, and Wenger maintained there was no agreement over how long he could play in midweek.
"At some stage it is the player who gives you the indication, you trust always the player," Wenger added.
"Sometimes you give him a few minutes to tell you how he feels and if he has pain, we cannot make an instant check-up with an X-ray, so it is the player who tells you if he can go on or not.
"I had no agreement (with England), no."