British heavyweight boxer Anthony Joshua has triggered the clause in his contract for a rematch with the Ukrainian Oleksandr Usyk, Joshua's promoter Eddie Hearn confirmed on Saturday.
Speaking to over-the-top subscription platform DAZN, Hearn said the fight could take place in spring next year.
He said: "He has got his head back in the game. He is training now and today we officially triggered the rematch for the Oleksandr Usyk fight, which we will see early next spring.
"We're looking for him to become a three-time heavyweight world champion. I think realistically March is when you're likely to see the rematch."
Joshua was beaten by Usyk in a unanimous judges’ decision at the Tottenham Hotspur Stadium on 25 September, losing his IBF, WBA, WBO and IBO titles in the process.
The result has put in doubt a highly anticipated bout between Joshua and his British counterpart Tyson Fury, who beat American Deontay Wilder in an 11th-round knockout on Saturday (9 October).
Fury’s co-promoter Frank Warren had said after Joshua’s defeat about a potential meeting between the two: "I don't see it happening now … The unification fight was there, such a big fight. Heartbreaking."
Following his victory in the third of his trilogy of fights against Wilder on Saturday, through which he retained his WBC title, it was confirmed that Fury's next opponent – as a mandatory challenger – would be another Dillian Whyte, another British fighter.
Both Joshua and Usyk are possible opponents for Fury after that, with much likely to depend on the result of their rematch.
A fight between Joshua and Fury had been lined up for August in Saudi Arabia before an arbitration hearing in the US ruled that Fury must first face Wilder in the third of their meetings as part of a contractual rematch clause.
Prior to his meeting with Usyk, Joshua signed a new promotional agreement with Matchroom Boxing that will run until the end of his career.