Deontay Wilder is preparing to snub a lucrative offer to sign with DAZN and therefore effectively end hopes of him fighting Anthony Joshua later this year, Press Association Sport understands.
The WBC heavyweight champion has been offered a reported $100million (£75.5million) to sign with the streaming service to first fight his mandatory challenger Dominic Breazeale and then fight Joshua, holder of the IBF, WBA and WBO titles, to unify all four.
It is understood that the interest from DAZN has instead led to a new offer being made by American broadcasters Showtime, who have long showcased his career, and that he is therefore likely to remain with them.
His decision is expected to be announced next week, and unless there is a significant change his commitment to Showtime would almost certainly rule out him fighting either Joshua or Tyson Fury at any point in 2019.
Fury's new contract with ESPN and the expectation that Joshua's fights will continue to be streamed by DAZN means that each of the world's three leading heavyweights will essentially be separated by their broadcasters in the US, which remains the sport's most influential market.
The development will also prove a further setback for Joshua, 29, and his promoter Eddie Hearn, who remains so influential at DAZN.
Wilder's entertaining draw with Fury in December provoked such a reaction that they had made fighting the 33-year-old American a priority, and when Fury signed with ESPN their hopes of making Joshua-Wilder significantly increased.
Hearn had spoken of his belief that DAZN's influence on negotiations meant that after long-term frustration a deal would finally be agreed, but Joshua could instead being left without an obvious challenger, after he expects to have furthered his profile by beating Jarrell Miller in New York on June 1.
The streaming service had most recently succeeded in signing Gennady Golovkin, making a third fight with Saul 'Canelo' Alvarez, who they have made the world's highest paid sportsman, increasingly likely for later this year.