While negotiations for a super fight continue to crawl along at a snail's pace, more and more voices are expressing their doubts that a Floyd Mayweather vs. Manny Pacquiao fight will happen at all. The most recent voice is multi-platinum rapper turned boxing promoter 50 Cent.

50, whose real name is Curtis Jackson, said during a recent interview that Mayweather wants no part of Pacquiao. "That's not going to happen," 50 said. "You heard me say it on film. It's not going to happen."

According to Jackson, Pacquiao presents too much risk for Mayweather at such a late stage in his career, when the zero in his loss column is the most important part of his legacy.

"What you wanna fight Pac-Man for under those circumstances when you can pick anybody you want to? Cause we wanna see the toughest fight?"

After a controversial loss to Timothy Bradley in 2012 followed by a knockout loss to Juan Manuel Marquez in 2013, Pacquiao appeared very vulnerable. He has since avenged the loss to Bradley, and soundly beaten Brandon Rios and Chris Algieri in his last three fights to restore his luster.

Mayweather has also continued his winning ways, but he was hit more than most expected in his first go-round with Marcos Maidana, and while he outclassed Maidana in their rematch, he didn't have the same electricity that he showed vs. Canelo Alvarez.

Mayweather has other options besides Pacquiao. A rematch of his 2012 clash with Miguel Cotto, who now has the WBC middleweight title, presents a very lucrative opportunity as does a matchup against Amir Khan, who has a large international fan base.

While being choosy about his opponents has played a role in his monstrous success both in the ring and financially, questions will likely remain long after Mayweather is gone about the legitimacy of his record compared to other all-time greats. 50 Cent touched on this with his interview.

"It don't happen if it don't have to," 50 said of Mayweather taking big risks. "Later when they look at his actual record and look at what he's done, they're still gonna have to say, 'Who do you think could have beat him if it would have happened this way?'"

50 also apparently told Chris Mannix something similar about the proposed super fight.