World champion Manny Pacquiao's promoter Bob Arum says he will ask the boxer to reconsider his objection to blood testing, raising the prospect that the proposed bout with American Floyd Mayweather could yet go ahead.
Just hours after Arum said that he was going to announce a new opponent for world champion Pacquiao, Mayweather's camp highlighted footage from a television documentary that appeared to contradict Pacquiao's objection to blood testing close to the fight.
Pacquiao has balked at Mayweather's demand for random blood testing within 30 days of the fight, preferring urine testing as he says losing blood weakens him - a stance which has threatened a highly anticipated and lucrative match-up.
But scenes from the HBO reality show 'Pacquiao/Hatton 24/7' which documented Pacquiao's build-up to his fight with Briton Ricky Hatton in May, showed the Filipino fighter giving blood.
Mayweather's camp said the scene was filmed just 14 days before the fight - a fact Arum said he wanted to verify before speaking to his fighter.
"I will transmit it to Manny once (HBO Sports president) Ross Greenburg establishes the actual date of the test in '24/7' and (the Mayweather camp) makes a proposal based on what Ross has come up with," Arum told ESPN.com.
"If that happens, I am sure I can convince Manny," he said.
Arum had set a Monday deadline for Golden Boy to accept a "final offer" in which both sides let the Nevada State Athletic Commission make the final decision on testing.
Leonard Ellerbe, CEO of Mayweather Promotions, said that there was no question of accepting that proposal.
"Random is random. We are not backing off and the ball is in their court," he told Reuters.
Arum then threatened to find another opponent for Pacquiao which in turn prompted another sharp response from the Mayweather team in a statement on Monday.
"Let the record be clear: Manny Pacquiao and his promoter Bob Arum are threatening to walk away from the largest fight in history," it said.
But the Mayweather camp also left the door open for further talks.
"Team Mayweather and Golden Boy Promotions is still open to the earlier discussions of having both parties work out a mutually agreeable understanding of the testing, which would be conducted by a mutually agreed upon agency," the statement added.
Pacquiao won the WBO title in November by stopping holder Miguel Cotto in the 12th round in Las Vegas.
The Filipino (50-3-2) won an unprecedented seventh title in seven weight classes to set up the best pound-for-pound showdown against unbeaten Mayweather (40-0) in what was expected to be among boxing's biggest earning fights.