Floyd Mayweather's route to boxing greatness has been carefully crafted without taking unnecessary risks, yet his announcement of a fight for a Japanese mixed martial arts organisation later this month could be his biggest gamble yet.
His opponent, young Japanese kickboxer Tenshin Nasukawa, is unbeaten in four MMA fights, although both Mayweather and Rizin revealed that the exact rules of the Dec. 31 Saitama showdown were still under negotiation.
If Mayweather, one of the greatest fighters to ever step into a boxing ring, does decide to try his hand at something new, he will need protection from the more extreme elements of cage fighting if he is to make any impact.
Despite being 41-years-old, his hands still pack a potent punch, but the addition of elbows, knees, kicks and grappling in MMA represent a huge challenge for a boxer boasting an unblemished 50-0 record dating back to 1996.
Throughout his professional career, the American was famed for his defensive skills, with his precise footwork and elusive head movement making him an almost impossible target for even the best in the world to land a glove on.
But as his "Money" nickname and social media activity showing off his love of an opulent lifestyle indicate, his career has ceased to be all about belts and titles.
He is a self-made marketing machine and his ground-breaking bout against two-weight Ultimate Fighting Championship (UFC) champion McGregor also illustrates a creative approach to maximizing his value.
Mayweather now appears to have eschewed a lucrative boxing rematch against long-time Filipino rival Manny Pacquiao in favour of a play for a cross-over MMA audience, many of whom had abandoned boxing for the more visceral thrills of the octagon.
His fight against McGregor in Las Vegas turned into a full-blown media circus and his 10th-round TKO gave fans their money's worth, on the surface at least.
FINANCIAL MIGHT
A talented-but-limited amateur, McGregor had no business being in the ring with a boxer of Mayweather's calibre, and his shortcomings were soon exposed. When the American turned up the heat late in the fight, the brash Irishman had no response.
In the cage, it would have been a very different story.
There are six different punches in boxing, and had McGregor been able to call on a striking arsenal consisting of kicks and elbows, plus his grappling skills, the outcome would most likely have been a quick and painful defeat for Mayweather.
The boxer arrives at Rizin with no grappling background to speak of and Brazilian jiu-jitsu -- the martial art that forms the backbone of MMA exchanges -- cannot be perfected quickly.
A black belt in the sport can take 10 years or more to acquire.
Mayweather's possible conversion to a cage fighter will provide a fascinating spectacle, and the tantalizing prospect of a possible second meeting with McGregor, this time in an octagon, would send fans of both sports into a frenzy.
However, if such a contest does happen, the sporting spectacle itself will have little chance of matching the hype likely to precede it.
Mayweather possesses enormous financial might and it has almost become a ritual for fighters seeking a bumper payday and media exposure to call him out, as UFC lightweight champion Khabib Nurmagomedov did after he submitted McGregor last month.
It may simply be that he is trying to maintain the crossover audience he created with McGregor and that the Rizin bout will simply be boxing in a cage, rather than a ring.
But as with everything in modern combat sports, money -- and in this instance "Money" Mayweather -- will ultimately call the shots.
