The Gunners have failed to gain any consistency throughout the season after a slow start to their campaign and were embarrassed by their Italian counterparts at the San Siro in the first leg of their last 16 Champions League clash.
Petit, who enjoyed three successful seasons in North London, believes that the current crop at Emirates Stadium are below the usual standard and feels Wenger needs to make immediate changes.
"We shouldn't hesitate to talk about the end of the cycle," he told sofoot.com. "Regardless of age, we have to look seriously at certain players. Right now."
The Frenchman highlighted Theo Walcott, Aaron Ramsey, Andrei Arshavin and Tomas Rosicky as under-performing players.
"Certain young players haven't done enough to justify the confidence that Arsene has in them," he added.
"Walcott, somehow he's going to have to reach the next stage. It's been years that he's been at the same level.
"Ramsey, against Milan, I got the impression it was his twin brother on the pitch. In the way they behave, in their body language, we see they're not there anymore.
"You have to send out a strong signal. You have to say to Arshavin, and to Rosicky: 'Gentlemen, thank you, but goodbye'. And soon."
The 41-year-old was part of the French national team that won the 1998 World Cup and he believes his former manager needs to make big signings in order to bring silverware back to North London.
"What's needed is five or six players of real stature, great experience. Players between 27 and 30-years-old at most,” Petit said.
"Players with technical qualities, obviously, but also strong character. A group of guys who refuse to accept defeat, who inspire confidence in the rest of the team."
By Matt Maltby
