A final KO for Pacquiao-Mayweather bout

The official end of hope for a super-fight between Manny Pacquiao and Floyd Mayweather Jr. came Sunday when Pacquiao promoter Bob Arum announced he had signed a deal to stage an alternate Pacquiao bout against Joshua Clottey on March 13 at Dallas Cowboys Stadium in Texas.

Arum said Pacquiao will earn somewhere between $10 million and $20 million for the welterweight fight against Clottey (35-3), who lost a split decision to Miguel Cotto in his most recent fight in June.

Cotto later suffered a 12th-round technical knockout loss to Pacquiao in November, as the Filipino star won his record seventh weight-division world title and probably clinched for the second straight time the honor of fighter of the year.

Mayweather’s promoter, Richard Schaefer, resigned to the futility of his attempts to resurrect talks of a mega-fight that crashed in a dispute over drug testing, told The Times on Sunday that Mayweather is engaged in “advanced negotiations” with another opponent and also plans to fight March 13 at MGM Grand Garden Arena in Las Vegas.

HBO will have to decide whether to broadcast the Pacquiao fight or the Mayweather bout on pay-per-view. Arum’s company, Top Rank, has previously staged its own pay-per-view cards.

Mayweather (40-0), considered with Pacquiao as one of the top two boxers in the world, is expected to fight New York’s Paulie Malignaggi (27-3).

Arum said he doesn’t plan to revisit a Pacquiao-Mayweather fight until the fall, after Pacquiao (50-3, with two draws) runs for a congressional seat in the Philippines in May.

The scrapped bout, which would have guaranteed both boxers more than $25 million, also deprives boxing of a major event many fight experts predicted would have received widespread attention in the mainstream sports world.

Mayweather and Pacquiao failed to strike a deal because of their heated dispute over a blood testing protocol for possible performance-enhancing drugs. Mayweather first requested testing beyond that performed by the Nevada State Athletic Commission.

Pacquiao, who has sued Mayweather for alleged defamation because of statements implying the Filipino star has used those drugs, wouldn’t accept a blood test closer than 24 days before the fight. Mayweather wanted the fighters to be subject to blood tests up to 14 days before the fight.

Referring to the Mayweather fight, Arum said that “the horse has left the building.” He instead expressed enthusiasm for the fight against Clottey, 32, whom Arum also promotes.

Clottey’s most notable victories have come against Zab Judah and Diego Corrales. “It’ll be a good test for Manny,” said Pacquiao’s trainer, Freddie Roach. “A lot of people thought Clottey beat Cotto. This will be a good action fight, just what Manny needs.”

Pacquiao was scheduled to arrive in the U.S. on Sunday night, and Roach said they will start training today at Roach’s Wild Card Gym in Hollywood.

Arum said seating capacity for the Pacquiao-Clottey bout will be 50,000, creating a unique atmosphere.

Schaefer said that Mayweather is also willing to later fight Pomona’s Shane Mosley, a pairing that would conclude years of jawing between the gifted foes who have long been near the top of the world’s best-pound-for-pound lists. Mosley is a world welterweight champion, with a title-unification bout against Andre Berto scheduled for Jan. 30 in Las Vegas.

“At 147 pounds, the man to beat is ‘Sugar’ Shane Mosley,” Schaefer said. “Floyd will take that fight and will shut up all those who are saying he’s a coward.”

lance.pugmire@latimes.com