Mosley's age will have a lot to do with it, Mayweather insists.

Mosley is 39 years old and will be turning 40 four months after his 12-round battle with the speedy punching machine Pacquiao, who turned 32 last December.

"I don't think Shane really has too much left at 39," said the brash, unbeaten American of the fighter he dominated for 12 full rounds in his last ring appearance in April 2010.

"I think that was his last hurrah," added Mayweather in a rare interview he granted to FightHype.com.

Mosley came close to knocking out Mayweather in their non-title fight in Las Vegas after hurting the controversial boxer in the second round, but never got his game going when Floyd Jr. began to apply the pressure from the third round onwards.

Five months later, Mosley settled for a split draw against average fighter Sergio Mora in a similar non-title bout set for 12 rounds.

Mayweather said Mosley's fight with him definitely took its toll on the aging boxer from Pomona, California.

"I think he was in a grueling fight with me," said Floyd, owner of a 41-0 record, with 25 KOs.

"It was a very tough fight for him. From the outside looking in, people didn't realize how tough of a fight it was with me. But it was a tough fight for him."

Asked if he's rooting for a Mosley victory over Pacquiao four months from now, Mayweather responded quickly, 'Absolutely.'

"Shane is a great guy and I wish him nothing but the best in his fight. I take my hat off to Shane for being a tough competitor. He's a future Hall of Famer," Floyd added.

Then again, Mayweather can't seem to say in all honesty that Pacquiao, the ring star whom the world wants Floyd Jr. to fight, has all the tools to beat Mosley and perhaps send him to retirement for good.

All Floyd could say was: "We can never say what’s going to happen in the heat of the battle." –

JVP, KY, GMANews.TV