This is like the 3rd time Mayweather has run his mouth about this and I wish he would just shut up. It will never happen. Also, comparing Boxing to MMA or K1 is ridiculous. It's like saying that an olympic wrestler couldn't compete in boxing. You think?
Anyway, Mayweather would be tooled by Sean Sherk. There's a perception that Mayweathers' hand speed would be enough to defend the shot which is total nonsense. This fight would be a ref stoppage due to elbows in the first round.