Dzeko, 25, arrived at Eastlands in January in a £27 million move from Wolfsburg after building a formidable reputation in Germany. The Bosnia striker scored a remarkable 66 goals in 111 Bundesliga games and earned a lucrative four-and-a-half-year deal with City in the process.
However, like Chelsea's former Liverpool striker Fernando Torres, a change of club in mind-season has seen a downturn in Dzeko's fortunes. Dzeko was an unused substitute in the FA Cup semi-final victory against Manchester United and could be back on the bench on Monday against Blackburn at Ewood Park.
Mancini believes the future is bright for his expensive buy, who is waiting for his first goal in the Premier League. Dzeko has found the target four times in England, twice against Notts County in the FA Cup - City needed a replay - and twice against Aris Salonika in the Europa League.
Mancini said: "It is difficult for him, it is difficult for me, but it can happen when you change teams. It is important he works hard, only this. I believe Edin is one of the top strikers in Europe but sometimes incredible things happen to strikers. You can score, you don't know why.
"On the other hand, (Wayne) Rooney did not score for months, the same for Torres. This is an incredible situation for a striker. But I am sure next season Edin will be fantastic for City. Now we have six games and the FA Cup final and Dzeko can score important goals in this time.''
City are on course for a place in the Champions League while Blackburn are in freefall after ten league games without a win. Italian striker Mario Balotelli looks set to retain his place and keep Dzeko on the bench as Carlos Tevez has a hamstring injury.
With defender Micah Richards also absent with a similar problem, Pablo Zabaleta is set to stay in the team following the Wembley triumph. Balotelli incensed the United players, particularly Rio Ferdinand, with the manner of his celebration after their win.
But Mancini will not penalise the 20-year-old, adding: "Have I spoken to him about the incident? No. I watched it on TV and I don't think it was an important thing.''