After announcing he would take on Nasukawa at the next Rizin Fighting Federation event in Saitama at a news conference in Tokyo this month, the American reneged on his commitment to the contest upon his return to the United States.
Mayweather said on his Instagram account that he only agreed to a three-round exhibition in front of a small group of wealthy spectators for a very large fee, with no intention of it being represented as an official fight card or televised worldwide.
However, a statement from Rizin FF CEO Nobuyuki Sakakibara on his unverified Twitter account indicated the Dec. 31 fight was back on, although the rules and duration of the bout have yet to be determined.
"The misunderstanding with Floyd Mayweather has been resolved," Sakakibara said in a tweet posted on Friday, alongside a photograph of himself and Mayweather.
"He will fight with Tenshin Nasukawa on New Years Eve for RIZIN 14. I will explain the details once I am back in Japan."
Sakakibara is planning to hold a news conference on Saturday to provide further details.
The 41-year-old Mayweather retired from boxing for a second time in 2017 with an unblemished 50-0 record after an illustrious career in which he won world titles at five different weight classes.
However, he has never competed professionally in any other form of combat sport, making his decision to sign with an MMA brand all the more surprising.
No fighting rules were announced at the initial news conference and the terms of the fight will need to be verified before fans can take Sakakibara's claim seriously.
In a video posted on the TMZ Sports website https://www.tmz.com/category/tmzsports on Wednesday, Mayweather indicated he was interested in making the contest happen but reiterated that it was to be an exhibition.
"No, it wasn't supposed to be an official fight, no. An exhibition, a small nine-minute exhibition," Mayweather said in Los Angeles.
"Rules? It is going to be a little boxing exhibition. No kicking at all. I will just be moving around with the guy for nine minutes."
Whatever eventually happens, Mayweather expects to be paid handsomely for his services.
"How much am I getting for this exhibition? If I do it, it will be the highest paid exhibition ever," he added. "Just for promoting this event, just so far, I have made seven figures."
(Reporting by Jack Tarrant; Editing by John O'Brien)
