Oleksandr Usyk plans to have "three more fights at the very most" before retiring, including a heavyweight unification bout with Tyson Fury.
The 35-year-old holds the WBA Super, IBF, WBO, IBO and The Ring heavyweight belts after defeating Anthony Joshua for a second time in last month's rematch.
Usyk's split-decision victory over Joshua in Saudi Arabia was supposed to clear the way for a unification bout with Fury for all the belts in the sport’s blue-riband division.
However, with Usyk ruling out a return to the ring this year, Fury is now in advanced talks with Joshua over a 'Battle of Britain' showdown in December.
Usyk is hopeful of facing Fury down the line, with super-middleweight champion Canelo Alvarez also on his list of targets before ending his career on home soil in Kyiv.
"I can have three more fights at the very most," Usyk said in an interview posted on his YouTube page.
"It is the most realistic to be in my top form. With Fury, Canelo and a farewell fight at Olympiyskiy.
"With Canelo he said that he wanted to fight me. It would be a freak fight just for the sake of earning money.
"I only need to beat Fury and then it is time to retire for me. The unification of all the belts is much more important than just a fight or another defence.
"I want to outbox Fury and I don't want to work that much just for another defence. There is much more that I can achieve."
Canelo is the undisputed super-middleweight champion after claiming victory in the final fight in his trilogy with Gennady Golovkin in Las Vegas last weekend.
The weight disparity between Usyk and Canelo makes any bout difficult to arrange, but the latter confirmed last month he is interested in facing the Ukrainian.
"It's difficult but I don't care," he said. "I like that type of challenge. I don't care. It's going to be difficult I know, but I love boxing. I love being in that type of situation."