Mayweather not going for the gold

There was a time, not very long ago it seems, when possessing a major title belt represented greatness. Every fighter once strived to own at least one.

Not anymore.

When Floyd Mayweather Jr. and Shane Mosley enter the ring Saturday night (HBO pay-per-view at 9 ET), the atmosphere inside MGM Grand Garden Arena will have a championship-bout feel.

However, there won't be a single belt up for grabs. That sits quite well with Mayweather.

He couldn't care less about the World Boxing Association welterweight title belt that Mosley currently owns. Being a champion is no longer on Mayweather's priority list.

Legacy and money motivate Mayweather now.

"At this level, it's not about belts," Mayweather's top adviser Leonard Ellerbe said. "It's about fighting … to improve his legacy; and it's about money.

"Floyd's already the best fighter in the world. Why does he need to fight for a belt to prove that?"

Few would question Mayweather's status as an elite boxer. Only Manny Pacquiao challenges him for top billing on most pound-for-pound lists.

Despite an impressive 40-0 (25 knockouts) professional record, there are some who doubt the validity of his success. The most common knock on Mayweather is his quality of opposition.

He takes issue with that criticism. It's a challenge to his legacy.

"No one gives me credit for who I have fought during my career." Mayweather said. "Shane is a solid welterweight with great accomplishments, but I have been fighting these kinds of fighters my whole career without much appreciation."

Count Mosley among those who question the quality of Mayweather's opponents, at least his 147-pound challengers. He believes Mayweather has avoided stiff competition too long, and it's time to step up.

Mosley plans to prove he, not Mayweather, is the best welterweight today. There is no doubt in Mosley's mind that this time Mayweather has bitten off far more than he can chew.

"He hasn't fought another top welterweight; I'm the first one that he's fought who's a world champion," said Mosley, who will carry a record of 46-5-0 with 39 KOs into the ring. "There are [several] great welterweights out there that he could have chosen to fight instead of fighting the ones that he fought."

Mayweather considers himself the best boxer ever, but the type of criticism Mosley and others have leveled against him makes it difficult for most observers to take his all-time best claim seriously.

Defeating Mosley, and doing so in impressive fashion, will give those same critics reason to re-examine their position on Mayweather's place in boxing history. Regardless of what happens Saturday night in Las Vegas, Mayweather believes he's done enough already to be rated boxing's all-time best.

He doesn't base his opinion on talent and professional record alone. The amount of money a fighter generates factors heavily into his equation. For Mayweather, pay-per-view buys is now a key indicator of a fighter's greatness.

"I got respect for Sugar Ray Robinson; I've got respect for Muhammad Ali," Mayweather said. "What makes them better than I am? Because they fought a thousand fights?

"In my era, it's totally different. It's pay-per-view now, so things change. It's out with the old and in with the new.

"Muhammad Ali is one hell of a fighter, but Floyd Mayweather is the best. Sugar Ray Robinson is one hell of a fighter, but Floyd Mayweather is the best."

With these words, Mayweather has significantly upped the ante. His legacy will be on the line Saturday night, but that is a big motivating factor for him.

Mayweather wouldn't have it any other way.

"At this point, it's about enhancing [my legacy]," he said. "I've accomplished many things that many fighters weren't able to do in this sport. With Mosley, [a victory] is going to … enhance my legacy."

Mayweather won't go into details on how he intends to whip Mosley. He does offer a glimpse of what viewers are likely to see when the punches start flying.

"Shane may be loading up with wide shots, and not using a full jab; I use a fuller jab," Mayweather said. "When I shoot my shots, I look at my opponents and I look where I'm punching.

"When Shane punches, a lot of times he closes his eyes … go back and look at some of his fights. … We're two totally different fighters."

Enhancing their boxing legacy is a desire Mayweather and Mosley will have in common. Mosley is 38 years old, and this fight might be his last opportunity to convince boxing enthusiasts that he deserves a spot among the all-time greats.

He's old-school and would love to have his WBA belt on the line Saturday night. For Mosley, fighting for and retaining the belt would add credibility to his accomplishment.

While the WBA 147-pound belt has no value to Mayweather, it remains important to Mosley. His promoter, Golden Boy Promotions, continues to petition WBA officials to put its belt on the line just for Mosley.

"It is not a WBA championship fight," Golden Boy CEO Richard Schaefer said. "However, we are currently discussing with the WBA that for Shane, Shane would be defending his belt.

"It's a non-WBA title fight. The two best fighters fighting each other. That's at stake here."

Not long ago, it seems, every boxer wanted a title belt around his waste. That isn't the case today.

Mayweather represents a new way of thinking: Get paid. Period.

Mosley is old-school: He too wants to make as much money as possible, but owning a championship belt still matters to him.

Mayweather and Mosley will put their legacies on the line Saturday night, but the future of boxing's sanctioning organizations also might be at stake.

Franklin McNeil is a contributing boxing/mixed martial arts writer for ESPN.com. He appears regularly on ESPN.com's 'MMA Live.'