Arsenal are heading into a season without Arsene Wenger in charge for the first time since 1996, while new boss Unai Emery has been handed five new players - Stephan Lichtsteiner, Bernd Leno, Sokratis Papastathopoulos, Lucas Torreira, Matteo Guendouzi - to bed in.
And given that the Gunners finished a distant sixth last season, retired striker Kanu, who spent five years with the club and won two Premier League titles and two FA Cups, believes it will be too much of an ask to bridge that gap at the first attempt.
"If it happens and they win the league, it's a miracle," he is quoted as saying by BBC Sport.
"It takes time for the newcomers, the new signings, to adapt. We have to allow time for him to bring his own style and the way he wants to play."
"For the new manager, it's going to be a very big challenge; the fans want them to perform in the league in his first year, which is always difficult for a new coach," Kanu said.
"It's a very big club - coming into a big club you need a trophy, so if you don't win the league, you need to win the others. It's hard, but that's what you expect of a coach of that stature and a big club."
Kanu is set to lead a charity game in aid of the Kanu Heart Foundation next month that will see a 'Premier League Masters' team featuring the likes of Robert Pires and Sol Campbell take on a team of 'African All-Stars'.