Wilshere had become a regular for the 13-times English champions before he suffered an ankle problem that caused a long-standing knee injury to flare up.
"It's massive for him to come back," manager Arsene Wenger told a news conference on Thursday ahead of Saturday's clash with league leaders Chelsea.
"When you are out for so long, it's massive to take. It is fantastic for him," added the Frenchman.
"What he's gone through will make him stronger. It's a good test for your mental strength."
Wilshere had forced his way into the England setup before he limped out of a pre-season friendly last year then had various setbacks in his recovery, though Wenger never doubted the youngster's resolve to get back to full fitness.
"I always thought he would come back. Wilshere has had ups and downs. He was focused, especially in the last three months," Wenger said of the 20-year-old, who resumed full training a week ago.
"We have to be a bit cautious. We need to manage him well. He needs a few games in the reserves," added Wenger.
There was more good news for the north London club when Wenger said defender Thomas Vermaelen would be fit for Saturday's visit of the European champions.