Tony Bellew's proposed fight with Oleksandr Usyk for all the world cruiserweight belts has been thrown into doubt after the Ukrainian was ordered to make a WBA title defence.
The Merseysider had been close to agreeing a December clash against the World Boxing Super Series winner, but the WBA has this week reportedly ordered Usyk to next face 'champion in recess' Denis Lebedev.
Bellew's promoter Eddie Hearn has admitted his fighter will either challenge Usyk to become undisputed champion or retire, and fears the bout can no longer be staged in 2018.
"The only way that Usyk versus Bellew happens is if all the belts are on the line," Hearn told Sky Sports.
"We will have to see what happens but certainly yesterday's news means Usyk versus Bellew is unlikely for 2018."
Speaking last week, Usyk's promoter Alexander Krassyuk had welcomed a battle with Bellew in Britain.
"Usyk has become Olympic champion in England and he is looking forward to defending all of his four belts," Krassyuk told Sky Sports. "That will be a great honour for him and his team."