Sterling, however, has thrived under new boss Guardiola's stewardship, with the England international's four goals and three assists in six Premier League starts helping unbeaten City climb to the top of the table.
"Raheem is back on track to be one of the world's top players. He is already one of the world's top young players but (can be) one of the world's leading players," Rodgers, who managed Sterling for three seasons at Liverpool, told British media.
"He's dynamic, super-quick and has great qualities and now has a clear plan of the team he's playing in. For a season or so he drifted -- maybe not so much to do with him. He has to be in a clear structure, with a way of working.
"He just needed to regain his identity, what he is. He's clearly working now with a coach who is very clear in terms of how he wants to play and I think when you have that with Raheem you maximise what you get out of him."
Celtic will look for their first win in the Champions League group stage this season when they host City on Wednesday.
(Reporting by Shravanth Vijayakumar in Bengaluru; Editing by John O'Brien)
