The Manchester City manager explained that the Spaniard was one of a number of strikers he considered during the transfer window of January 2011.
The Italian claims that Dzeko offered certain qualities that Torres did not have and also that price was also a major factor in deciding not to take the latter.
In the end, City took Dzeko from German club Wolfsburg, while Torres moved to Chelsea for £50m - almost twice as much as the Bosnian cost the Premier League champions.
Mancini told the Independent website: "Two years ago we had a chance. We decided on other players, also because of his cost.
"There were four or five strikers we talked about. We chose Edin because we were missing the qualities he had - strong in the air and different from Torres."
The two teams meet on Sunday at Stamford Bridge and Mancini is aware of the Torres danger: "I think he is a good player. Every striker can have a difficult moment but for me he is always dangerous."