If a Floyd Mayweather vs Devon Alexander fight isn't just Floyd messing with everyone, then the potential May 4 clash between the two won't have Devon Alexander's IBF welterweight title on the line, as the sanctioning body says they cannot approve that bout due to Alexander having a signed contract to face mandatory challenger Kell Brook:
"We have not received any requests or information on this from either camp. Because Alexander is under contract to fight Brook he would not be granted an exception to fight Mayweather."
Alexander (24-1, 13 KO) and Mayweather (43-0, 26 KO) would still be able to fight for Mayweather's WBC welterweight title, which Floyd won in September 2011 from Victor Ortiz. He's never defended the belt, but the WBC hasn't stripped him or made him champion in recess or anything, because Floyd fights mean a lot of money.
Brook (29-0, 19 KO) has Matchroom backing him as much as they can, and now the IBF is in his corner, too. He says on Twitter that however he has to get the belt, he's going after it:
I have been in camp for 12 weeks I want to do damage. Alexander, a vacant belt or even Mayweather I don't care!
So Kell Brook, we can be relatively certain, will be fighting for the IBF welterweight title soon. We do not know for sure that it will be against Devon Alexander.
If Alexander is out of a fight with Brook for real, then it gets pretty ugly going by the organization's rankings. Jan Zaveck, Rafal Jackiewicz, and Randall Bailey are the next three in line -- Zaveck is busy with Keith Thurman hunting a WBO title shot, Brook already wiped out Jackiewicz, and Bailey stunk out the joint in his last two fights, save for the part where he exploded Mike Jones' face.