Mayweather vs. Pacquiao
Manny Pacquiao (right) of the Philippines takes a punch from Floyd Mayweather Jr. of the U.S. in the second round during their May 2 title fight in Las Vegas. Reuters/Steve Marcus

Following his win against Manny Pacquiao in May, welterweight champion Floyd Mayweather has found himself in a curious situation. A rematch against the Filipino icon would have made perfect sense considering the record-breaking financial figures of the first fight, but Pacquiao's shoulder injury prevents another mega-fight from happening in 2015. Now Mayweather is in search of his next challenger and the candidates don't look nearly as promising.

The welterweight division is littered with talent, but Mayweather's September fight plans were expected to include a high-profile opponent in what could be his last fight. Amir Khan was thought to be the most logical opponent for Mayweather, but Khan provided a less-than-inspiring performance in a win against Chris Algieri on May 29.

The one boxer who might garner some interest is Keith Thurman. The 26-year-old defeated Robert Guerrero in March, and will be fighting Luis Collazo in July. Should Thurman win convincingly he could perhaps get a shot at the champion. He told On the Ropes Boxing Radio that he wants a shot a Mayweather.

"We're definitely in line for the Mayweather shot," Thurman said. "We've been in line for the Mayweather shot for a minute but it doesn't matter who I fight in the welterweight division.

"I would love Floyd Mayweather. He's the man. Until the man retires, he's the man.

"I want to be a legend and the best way to become a legend is by taking out a legend, and that would be Floyd Mayweather."

While Thurman is undefeated, it's possible that Mayweather may consider a boxer with more drawing power to boost pay-per-view sales. English star Kell Brook also has an undefeated record, and could generate strong interest because of his British fanbase. Brook also made a name for himself by defeating highly regarded Shawn Porter.

But either Thurman or Brook would be a financial letdown for Mayweather in what could be the last fight of his career. The consensus opinion is that a fight against a Mexican boxer would bring about a great deal of interest, but there is no available elite Mexican boxer in the division. Canelo Alvarez, who Mayweather defeated in 2013, is reportedly interested in fighting Miguel Cotto.

Mayweather is looking to finish his career as an undefeated champion. He has a 48-0 record, and is a win away from tying heavyweight champion Rocky Marciano's illustrious 49-0 record.