Balotelli is sidelined with a knee injury and the striker said he would be out for eight weeks.
However Mancini responded: 'He is in Italy today and his knee is okay. I think he may be ready at the end of October, in four to five weeks.'
Down but not out: Balotelli will return to action for City sooner than expected
The news comes a boost to City who had thought they would be without their new signing until the middle of December.
The Italian forward, 20, had earlier stated that his prognosis was much worse, ear-marking City's trip to his homeland toplay Juventus in mid-December as a potential return date.
Manchester City squadHart, Given, Richards, Zabaleta, Kompany, K Toure, Boyata, Cunningham, Lescott, Boateng, Silva, De Jong, Y Toure, Barry, Vieira, Milner, Johnson, Tevez, Adebayor, Jo, Santa Cruz.
He said: 'It's going to be around six to eight weeks,' adding about life in Manchester, 'It's OK, I'm calm about it.'
His return will come as a big boost to Mancini who has been heavily reliant on the continuing good form of Carlos Tevez so far this season.
Micah Richards could come into contention for the Europa League match against Juventus on Thursday after sitting out the victory over Chelsea with a hamstring injury.
Shaun Wright-Phillips is doubtful with a knee problem while Wayne Bridge and Aleksandar Kolarov remain absent.
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