The Italian does not believe the decision to sell Balotelli to AC Milan in January played a part in their failure to retain the league title.
Balotelli had scored just two league goals before moving to the San Siro, but has been in prolific form since, scoring eight in nine appearances.
Mancini said: "For Mario it was better to go back to Italy and even with Mario I think the season would have been the same."
He added: "It is difficult when you consider why you don't score enough goals. Last year we scored 20 goals more than this season and we are missing them, it's too many.
"If we had scored another 10-20 goals we could have been fighting for the league."
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