Dzeko has failed to hold down a regular place in the Blues' attack since joining from Wolfsburg just over two years ago and says he loves the Bundesliga.
The Bosnian international said: "I love the Bundesliga and I will return to the Bundesliga. The only thing I don't know is when."
Dzeko, who was top scorer in the Bundesliga in 2009-10, rejected claims he has met Borussia Dortmund boss Jurgen Klopp, but admitted he admires the German champions.
"That's not true," he said. "There is a lot of talk and a lot is written. If you believed every word, I'd be playing at FC Bayern or AC Milan by now.
"Dortmund are a top club. Everyone in Europe can see that and with Jurgen Klopp, they have a great coach working there."