Just got wondering who actually beats him??

I've just gotten finished reading an article about Matthysse joining up with Al Haymon over on BadLeftHook when I got thinking about something. It mentioned in the article about the idea of the guy who comes out on top of Lucas, Peterson and Garcia maybe moving up to Welterweight.

This got me thinking about something ahead of Floyds fight with Guerrero. between 140, 147 & 154, is there anyone there that anyone GENUINELY thinks could beat Floyd Mayweather?? I have no definites myself, but a few who maybe could have a better shot than Guerrero this Saturday. I'd like to hear anyones shout here..

Definately Maybe:
Saul Alvarez - 154 (would Alvarez be a bigger challenge at this stage than DeLaHoya was back when)
Gennady Golovkin - (if) 154 (Could Golovkin make 154 like he says and is he the real deal?)

Maybe:
Lucas Matthysse - (if) 147 (Is Matthysse any better than Castillo was at Lightweight?)

Personaly, I'd like to see Mayweather in with Matthysse at 147 and with Alvarez at 154. Both will happen eventually I think, before Floyd calls time on it.

I don't think Alvarez of GG stand any chance of beating him and Matthysse a very slim shot. I actually think Bradley has a good shout - and Khan - as Mayweather is'nt a huge puncher - Garcia no chance and same with Lamont -

Saul at Light middle would be good challenge.
Sergio at middle would beat Floyd, just too huge a jump.
No body at Welter can beat Floyd.