The 21-year-old England star was out for more than a year with knee and ankle problems between 2011 and 2012 and underwent a minor operation earlier this summer.
But he was able to join the club's tour of Asia and is happy with his preparation with the new season less than three weeks away.
He told the Arsenal website after the tour of Asia: "I felt better and better every game. It's difficult with the conditions. You struggle to catch your breath.
"The performances have got better every game and the opposition have got harder every game so it's good preparation. We've got the Emirates Cup coming up now and then Manchester City and then the season starts so we're going to be flying.
"I'm probably 80% fit. We've got a couple more tests and then we'll be ready."
Wilshere also highlighted the promise of England U19 internationals Chuks Aneke and Chuba Akpom, who were on the senior tour.
He said: "I remember when I was their age. It's good to come away and get used to being around the first team and learning from the manager, who is good at bringing young players through and breaking them in slowly.
"They've done well and hopefully they can get in the Emirates Cup squad and really show the home crowd what they can do."