Unbeaten five-time champion Floyd Mayweather blamed seven-division titlist Manny Pacquiao for the demise in negotiations of their proposed blockbuster bout that was slated for March 13 at the MGM Grand in Las Vegas.

The talks failed on Wednesday, even after two days of mediation -- including Tuesday's nine-hour meeting in Santa Monica, Calif. -- centering on a drug-testing impasse involving random blood-checking and urinalysis leading up to their fight for Pacquiao's WBO welterweight (147 pounds) belt.

FanHouse has learned that welterweight contender Joshua Clottey (35-3, 20 KOs) of Accra, Ghana, will be named as Pacquiao's next opponent. A dangerous puncher with a resolute chin, Clottey, is promoted by Arum. But Clottey is an often-avoided fighter who has had a tough-luck career.

Pacquiao-Clottey should take place on March 13 or March 20.

The 31-year-old Pacquiao (50-3-2, 38 knockouts) had agreed to be randomly blood-tested no closer than 24 days of the bout with Mayweather (40-0, 25 KOs), who wanted both fighters to be open to being randomly checked all the way up to the fight and afterward.

In a statement read to FanHouse by Mayweather's adviser, Leonard Ellerbe, the unbeaten fighter railed against the notion that he was the reason for the death of a matchup that was likely to produce a career-high $40 million for each combatant.

"Throughout this whole process, I have remained patient, but at this point I am thoroughly disgusted that Pacquiao and his representatives are trying to blame me for the fight not happening when clearly the blame is on them," said the 32-year-old Mayweather.

"First and foremost, not only do I want to fight Manny Pacquiao. I want to whip his punk a**. Before the mediation, my team proposed a 14-day, no-blood-testing window leading up to the fight. But it was rejected," said Mayweather. "I am still proposing the 14-day window, but he is still unwilling to agree to it -- even though this is obviously a fair compromise on my part as I wanted the testing to be up until the fight and he wanted a 30-day cut-off."

"The truth is he just doesn't want to take the tests. In my opinion, it is Manny Pacquiao and his team who are denying the people a chance to see the biggest fight ever," Mayweather continued. "I know the people will see through their smokescreens and lies. I am ready to fight and sign the contract. Manny needs to stop making his excuses, step up, and fight."

Believing that Mayweather's side has accused him of steroid use, Pacquiao has filed a lawsuit charging defamation of character against Mayweather, his father, Floyd Mayweather Sr., and Roger Mayweather, as well as Richard Schaefer and Oscar De La Hoya of Golden Boy Promotions. Golden Boy represented Mayweather in the negotiations.

Top Rank Promotions' CEO Bob Arum, who said that he plans to name an opponent to replace Mayweather, "on Friday," said Mayweather "can say anything that he wants after the train has left the station."

"Floyd's actions over the last several weeks show that he didn't want to fight against Pacquiao. Excuse after and excuse was made, and he trumped the lie by accusing Pacquiao of taking steroids so that he doesn't have to fight him," said Arum.

"Now Pacquiao's fought 54 times -- including 10 times in Nevada. And he's given countless random drug tests. And he has never been found to have taken any performance-enhancing drugs or any substance prohibitted by the Nevada State Athletic Commission. Ever," said Arum.

"Manny's not going to be bullied by a thug. Or labled a cheater. In more than four decades of boxing, great champions like Muhammad Ali, George Foreman, Sugar Ray Leonard, Marvin Hagler and Thomas Hearns have fought in Nevada under the rules of the Nevada Commission," said Arum. "As far as I'm concerned, this saga has ended. All that I can say to the public is that I'm sorry, because I, Bob Arum, made a mistake by trying to appease Mayweather."

Arum had planned to name newly-crowned WBA junior middleweight (154 pounds) champion Yuri Foreman (28-0, eight KOs) of New York as a replacement for Mayweather against Pacquiao on either March 13 or March 20, the latter date being at the Thomas & Mack Center in Las Vegas.

But the 5-foot-6 Pacquiao, who would be after his eighth crown in as many weight classes, nixed that idea, citing a height disadvantage against the 5-11 Foreman. Pacquiao made his decision after having watched videos of Foreman.

Arum would not say for sure any of the opponents he is considering, although he acknowledged that WBO junior welterweight (140 pounds) king Tim Bradley (25-0, 11 KOs) is on a short list.

A Bronx resident, Clottey is coming off of June's disputed 12-round split-decision loss to Miguel Cotto, and was supposed to take on former world champion Carlos Quintana of Puerto Rico in Atlantic City on the undercard of a scheduled bout Dec. 5 between WBO and WBC middleweight (160 pounds) champion Kelly Pavlik and Paul Williams.

But when Pavlik-Williams was canceled due to a staph infection on Pavlik's left forefinger, the entire card was scrapped, and Clottey was out of a fight.

The 32-year-old Clottey was ahead on points for the first four rounds of his unanimous decision loss to hard-hitting Antonio Margarito in February 2006 before injuring both of his hands, which slowed his momentum for the remainder of the bout.

Clottey had won five straight fights entering his loss to Cotto, including decisions over former world champions Diego Corrales and Zab Judah.