Floyd Mayweather vs. Tenshin Nasukawa Odds: Early Vegas Lines for Fight in Japan

Floyd Mayweather's latest comeback from retirement will see the undefeated boxing superstar taking on a different challenge when he fights Tenshin Nasukawa at Rizin 14 on Monday. 

Even though Mayweather vs. Nasukawa is taking place on a mixed martial arts show, it will be fought under boxing rules with three rounds lasting three minutes each. The result won't be counted on either fighters official record, per a release from Swanson Communications. 

Here are the updated odds heading into the New Year's Eve spectacle, via OddsShark.com. 

Rizin 14 Odds

Floyd Mayweather -260

Tenshin Nasukawa +200

In many ways, Nasukawa is the most unique fighter Mayweather has gone up against in years. The 20-year-old Japanese already has an established resume in kickboxing and mixed martial arts with a combined 32-0 record (28-0 in kickboxing).

Traditional boxing is new to Nasukawa, though he's been connected to the sport for years. He defeated former IBF flyweight champion Amnat Ruenroeng in a kickboxing match in February 2017 and is anxious to prove his credentials in a different fighting discipline. 

"It was a surprise offer but I accepted without hesitation," Nasukawa told reporters at the press conference announcing the fight. "It's the biggest moment in my life and I want to be the man who changes history. I'll do that with these fists, with one punch—just watch."

Eugene Hoshiko/Associated Press

One potential reason Mayweather may have been open to this challenge is because of his significant size advantage. Money is four inches taller than Nasukawa, who is listed at 5'4" on Sherdog.com. 

Nasukawa also competes in kickboxing at 126 pounds, but this matchup is a catchweight bout with a 147-pound limit. 

All of the rules are set up to favor Mayweather, which he seemingly admitted was a mandate in order to compete on the Rizin New Year's Eve show. 

"I'm gonna say this once again: Everything is always on my terms. I'm the A-side, always," Mayweather told reporters. "I'm not going to fight in an MMA ring. If I do fight in an MMA ring—boxing only."

Given how one-sided everything looks heading into this matchup, it's a surprise oddsmakers only have him as a -260 favorite. 

A possible explanation for that is in the official rules for the bout. Per ESPN.com's Dan Rafael, since the contest is an exhibition, there will be no judges or score rendered if it goes all three rounds. 

For all of Mayweather's assets in a boxing ring, he's never been a quick worker. He hasn't won via TKO in under three rounds since December 1998. He's 41 years old coming into this fight against Nasukawa. 

There is nothing to indicate the American will be able to end things within the nine-minute time limit. Nasukawa will have a difficult enough time trying to attack a bigger opponent, let alone strike him hard enough to knock him down. 

This is a fight designed to end without an official winner, but at least Mayweather will have some sort of tune up if he wants to get back in the boxing ring next year.