The Spaniard ended years of transfer speculation when he put pen to paper on a deal worth around £30m at the Nou Camp.
"If you look at him now, he's flying," Wilshere told the London Evening Standard. "It'd be nice if he came back one day - the door is always open for him because of what he did at Arsenal.
"You'd almost say he's an Arsenal legend now and I think the fans would welcome him back as well."
Fabregas joined Arsenal in 2003 from the Catalan club.