The Bosnia-Herzegovina forward - who scored 14 goals in 32 Premier League fixtures last term - was given the full support of his manager on Tuesday.
Despite an array of competition that includes Argentina star Sergio Aguero and new signings Stevan Jovetic and Alvaro Negredo, Dzeko will be City's main man up front, according to Pellegrini.
"We could've signed other players but I consider him (Dzeko) the main striker of the team and I'm sure his performance along the season will be really good," Pellegrini said.
"I very much trust him and I can say that every other player that have come are a support for a squad that needs to have more than one player in every position."
Dzeko has started just 16 matches in both of his full Premier League seasons at City but those numbers are likely to change given Pellegrini's faith in the 27-year-old.
Pellegrini is in Germany preparing for the Audi Cup pre-season tournament, which is hosted by Bayern Munich at the Allianz Arena, and also involves AC Milan and Sao Paulo.
Missing from City's squad is defender Matija Nastasic, while Aguero is also sidelined due to 'problems in his knee'.
Nastasic fell awkwardly in City's 1-0 Asia Trophy final win over Sunderland and the club is anxiously awaiting further developments on the severity of his problem.
"We'll know tonight (Tuesday) how bad Nastasic's injury is (and) whether he needs surgery," he said.
The former Malaga boss also expressed his joy at coming up against Pep Guardiola again, which could happen at the weekend.
Guardiola - formerly of Barcelona - signed a deal with Bayern Munich in January this year and he has already brought Mario Gotze and Thiago Alcantara to the club.
And Pellegrini has tipped the Bavarian giant to enjoy plenty of success under its new manager.
"It's a pleasure to be again playing for an important tournament especially with Pep managing Bayern Munich," he said.
"I'm sure he will complete a terrific season this year. I was lucky enough to share four years with him in the same competition, now it's different but we both still want to play good football.
"Bayern are a very important team in Europe, dominating in the last years. They reach always the final stages of Champions League and are at the top of the table in the Bundesliga and now with Pep I think they will be even more dangerous."