Eddie Hearn expects Anthony Joshua to fight cruiserweight king Oleksandr Usyk next year.
It is anticipated that undisputed cruiserweight champion Usyk will make the step up to the heavyweight division in 2019.
Hearn, Joshua's promoter, says the WBO, WBA, IBO and IBF heavyweight title-holder could well do battle with the Ukrainian in a mandatory bout next year.
Asked if the Briton and Usyk might step into the ring together this year, Hearn told Sky Sports: "No. That fight comes in 2020."
He added: "Usyk will fight in May, probably in his heavyweight debut, potentially against Alexander Povetkin.
"Then he'll have one more. Then it looks like the WBO will make him mandatory for Anthony Joshua. I see that fight happening in spring 2020."
Joshua's next assignment is a United States debut against Jarrell Miller at Madison Square Garden on June 1.
Usyk had a banner year in 2018 - which saw him receive Fight of The Year honors from most boxing outlets. He unified the entire cruiserweight division and won the first World Boxing Series Cruiserweight tournament. He saw action three times, all three bouts in hostile territory, and picked up victories over Murat Gassiev, Mairis Briedis and a brutal knockout of Tony Bellew.
Usyk signed a co-promotional agreement with Hearn's Matchroom Sport - for the sole purpose of secure a crack at Joshua and other Hearn promoted heavyweights.
Both Joshua and Usyk captured Olympic gold in the 2012 London games. Joshua won gold at super heavyweight, while Usyk picked up his prize at heavyweight. Usyk was initially rumored to start his career in the heavyweight division, but decided to start his pro run as a cruiserweight - with a move to heavyweight always being a future goal on his list.