While the Argentine duo of Carlos Tevez and Sergio Aguero have scored eight goals between them in two games since Tevez returned from a six-month absence, Dzeko and Balotelli - signed for a combined £50million - are too similar to make a good partnership in Mancini's opinion.
The City boss said: "Carlos can play with Mario, Sergio and Dzeko. The only players who can't play together are Mario and Dzeko because they are the same type of players.
"Technically they are different but they're the same player. For this, the two players can't play together. Only Mario and Dzeko can't play together because they have some problems.
"Dzeko didn't play very well against Arsenal but we made a big mistake when we conceded a goal three minutes from the end.
"If we'd drawn against Arsenal it was another point. But we can't do anything about it now."