OK, let's not even pretend. It's a publicity stunt. Mark Cuban, who was on "Dancing with the Stars" with Mayweather, is trying his hand at promoting MMA with his HDNet company. By getting Floyd Mayweather's name attached at a time when Mayweather is one of the world's hottest sports stars -- 850,000 buys for Mayweather-Hatton was not, as Kid Nate at Bloody Elbow described it, "very disappointing" in any way -- Cuban is buying himself attention in a sport that has one true ruling promotion and lots of second- and third-tier promotions that help the big boys and the sport in general be as good as they are.
Cuban's idea, really, is to come right in and very quickly be a competitor to UFC. It won't work, because this isn't a basketball team he bought and made a contender because he had the cash to do so. Who would Mayweather fight, if you even want to give this the slightest chance of actually happening? Nate at BE is right, it would be a tomato can or a completely one-dimensional, not especially skilled grappler. Someone that Floyd could catch coming in with a left hook.
As an aside, I do think that with real training and time put in, Floyd Mayweather is a guy that could actually be fairly successful. He is a marvelous athlete who works hard to be as great as he is.
But it won't happen. Mayweather is also using this just to keep his name in the news as the new Face of Boxing. Good for him, good for Cuban, but it's a waste of time for most of us. Floyd Mayweather is not going to go into mixed martial arts.