The veteran striker has joined Pioli in moving to Fiorentina this week.
At his presentation this morning, former AC Milan coach Pioli said: "At the end of the year, when I was at Milan, there was still no chance of Zlatan (Ibrahimovic) staying, and I specifically asked for Dzeko.
"He's a very valuable player who will raise the level of the team."
Asked about playing Dzeko, Albert Gudmundsson and Moise Kean together, Pioli also said: "We won't always be the same, but the idea of having them all play together is there. Then a lot will depend on their ability to work together. I repeat: the more quality players we have, the better our chances of winning.
"The game structures are fluid now, so I wouldn't think about formations. I want to transfer certain concepts to the team. The characteristics of the midfielders? I still have to understand the players I have at my disposal."