The England international joined Man City for £100 million ($129m) in 2021 but has struggled to make an impact at the Etihad Stadium.
This season, he has fallen down the pecking order with only six Premier League starts, and the former France international stated he must regain his form to earn a spot in England’s squad for the 2026 World Cup.
"We know that he can show so much quality, but we haven’t seen it this season. I don't know what's happening with him because Pep Guardiola seems to keep him on the bench. He doesn't have any confidence in Grealish anymore, he doesn’t believe in him and he doesn’t trust him because he's not in the starting line-up for Manchester City," Petit told pokerfirma.com.
"Jack’s in trouble with Pep Guardiola, but as well, he's out of the England team. He missed Euro 2024, and his international career is at a crossroads, his City career too.
"Grealish needs to ask himself, can I get into the England team and represent my country at the World Cup if I continue to be a bit-part player at Manchester City?
"If you want to play for your national team, you have to compete every single week in the starting line-up, you need to show the quality that you have and your ability as a footballer on the grass, and Jack hasn’t been able to demonstrate his ability for months now. I don't know what's happening with him. Did he lose the passion for the game?”
Petit added: "His motivation is not there anymore. The solution is simple: look in the mirror and ask yourself, how do you want the remainder of your career to go. Look at yourself, first. Find the answer. He hasn’t shown the desire or the fight to be a first team player for Manchester City. He needs to get that back if he wants to keep playing at the highest level."