It looks like the fight of the century between two of the sport's greatest athletes isn't going to happen.

The much-anticipated Manny Pacquiao - Floyd Mayweather Jr. bout set for March 13 at the MGM Grand is off, according to a report on ESPN.com. We've all heard these threats before, but this time it sounds serious.  

At issue was drug testing. Both fighters agreed to take random urine tests, but Mayweather, whose camp made allegations that Pacquiao used performance enhancing drugs, wanted random blood testing.  

Pacquiao initially didn't want to take any blood testes, but agreed to three tests: The first during the week of the first news conference, the second 30 days before the fight and the final test in the dressing room after the fight. 

It still wasn't enough for Mayweather, who insisted on random blood tests.

With both fighters refusing to budge, they enlisted the help of retired judge Daniel Weinstein. Weinstein had mediated disputes between Top Rank and Golden Boy Promotions in the past. 

Weinstein's steady hand wasn't enough as Top Rank boss Bob Arum told ESPN.com "the fight's off" from Las Vegas on Wednesday.

According to ESPN.com, Pacquiao agreed to relent a bit and take the second blood test 24 days before the fight. Pacquiao did the same thing prior to his fight against Ricky Hatton. The six-day concession still didn't appease Mayweather.

"Manny accepted what was on the table and Mayweather rejected it," Arum told ESPN.com. "[Al] Haymon and [Richard] Schaefer tried to convince Floyd all [Tuesday night] and [Wednesday] and he wouldn't agree to it. He didn't want the fight. He never wanted the fight. I always knew the fight wouldn't happen."

What does it all mean? It means neither fighter will collect on the $40 million they would've each received for the fight. It also means the 2007 tilt between Oscar de la Hoya and Mayweather will stand as the most watched PPV fight (2.44 million buys) ever.

advertisement | advertise on newsday

The Pacquiao-Mayweather bout was expected to approach three million buys.

As for each fighter, Arum said Pacquiao (50-3-2, 28 KOs) is likely to move up to 154 pounds and take on WBA Super middleweight champion Yuri Foreman.

It's anyone's guess who Mayweather (40-0, 25 KOs) will fight if the bout against Pacquiao can't be salvaged. Shane Mosley, Miguel Cotto, Paulie Malignaggi, Joshua Clottey and Tim Bradley are all potential opponents.

Photo credit: AP