The 30-year-old rejoined his boyhood club in September with the hope of recovering from surgery on a problematic left Achilles.
However, the striker struggled to regain his fitness and has faced disciplinary action for missing training on numerous occasions, with the most recent incident on Friday.
Adriano was expected to have contract talks with Flamengo on Tuesday, as he exceeded an agreement to miss no more than three training sessions, but has now taken it upon himself to leave the club.
The former Brazil international said: “I thought a lot, talked to my friends and family and came to the conclusion that the best thing to do is to return in 2013.
“I took this decision not only for me but also for Flamengo. I am almost recovered but will be missing for the final few rounds of the championship.
“The club has to concentrate on this final strait and I need to focus on getting back to 100% fitness and not to satisfy expectations.”
Adriano also revealed that he will continue to train and regain fitness with hopes of returning to action next season, whether at Flamengo or somewhere else.
He added: “I will continue training with even more rigor. I do not know if it will be in Rio but I can say that in 2013 I will be ready to enter the pitch.
“Thanks a lot to those who always support me. Believe me, this decision was made considering all.”
Twelfth-placed Flamengo are expected to announce Adriano’s departure on Tuesday.
