Floyd Mayweather Jr.'s mastery of the shoulder roll just forms part of his entire defensive repertoire, according to future Hall of Famer and former Money May's opponent Sugar Shane Mosley.

Mosley, who engaged in a 12-round battle but lost to the Grand Rapids native via unanimous decision in 2010, pointed out in an interview with Fight Hype that Mayweather's famous shoulder roll is not just the main reason behind his almost impregnable defense, believing the undefeated American fighter is doing all kinds of stuff to avoid getting hit and then unload his quick counterpunches.

"There's different things that Floyd does that people don't understand," stated Mosley, who recently lost to Australian boxer Anthony Mundine after quitting in the fifth round of their fight in November.

"Floyd is not just doing the shoulder roll. Floyd is doing other stuff too. They think that they can just do that [shoulder roll] and it nullifies everything like Floyd does, but it doesn't. That's the misconception," he added.

Mosley said Mayweather's superb reflexes along with his agility and hand speed made him perhaps the best defensive fighter in the history of the sport.

"I mean, Floyd is turning, he bounces a little bit, he gives them a little angles; I mean, he's doing different things. They're just trying to do one little thing that Floyd does, but he's doing all kinds of other stuff. That's what makes him him," Mosley added.

Mosley's comments came in the wake of Bob Arum's barrage at Mayweather, calling him a defensive fighter vulnerable against left-handed punchers like slugger Manny Pacquiao.

"Don't you understand why the Mayweather-Pacquiao fight won't and can't happen?" Arum said to ESPN. "I promoted Mayweather for over 10 years. One thing I learned over those years is that Mayweather doesn't like or won't fight southpaws," Arum stressed.

"Why? Because his whole style is geared for a right-handed fighter. And to compound that if the southpaw is really fast and moves, that would give Mayweather and his style a lot of problems, and it would really jeopardize Mayweather's record of an undefeated fighter," he added.

Mayweather has yet to pick his next opponent, but Great Britain's Amir Khan seems to be the clear-cut favourite now that he bested Marcos Maidana in an online pool on Mayweather Promotions Web site.