Los Angeles, CA -- (Sports Network) - Floyd Mayweather Jr.'s scheduled fight against lightweight champion Juan Manuel Marquez, originally slated for July 18, has been rescheduled for September 19 at the MGM Grand in Las Vegas.

The highly anticipated welterweight bout was postponed on June 14 because of a rib injury Mayweather sustained in training.

The fight will mark Mayweather's return from retirement, as he has not fought since December 2007, when he downed Ricky Hatton by TKO. The matchup is expected to be a spectacular showcase of skills, as the dynamic Mayweather (39-0, 25 KOs) established himself as one of the best pound-for-pound fighters in the world, winning championships in five different weight divisions.

If Mayweather is to dethrone Marquez, he'll have to defeat the native Mexican on that country's observed Independence Day.

"I am relieved to be cleared to fight as I was already looking forward to getting back in the ring," said Mayweather. "Trust me, September 19 is a great weekend for boxing, and all of my fans, of which there are many Mexicans too, can certainly hold on to their hats and sombreros when I get back in to the ring and show them what they have been missing these past 18 months. I will destroy Marquez and reclaim my rightful place as boxing's pound-for-pound king all in one night."

Marquez (50-4-1, 37 KOs) is the current WBA and WBO lightweight champion. He's also held featherweight and super featherweight titles.

"I am happy that Mayweather has been cleared to fight and we can get down to business on September 19," said Marquez. "This weekend is not just an important weekend for boxing, but even more so for all of the Mexican and Mexican-American people I will be fighting for who will have a great reason to celebrate my win over Mayweather, which will be for all of the people and for the entire country of Mexico that night."