Manny Pacquiao's refusal to allow his blood to be taken close to his proposed showdown with Floyd Mayweather Jr. as part of an Olympic-style drug testing procedure has put the mega fight of 2010 in jeopardy, according to a press release from Golden Boy Promotions, which represents Mayweather.

According to the press release, which was sent out on Tuesday, Golden Boy Promotions was informed that Pacquiao is refusing to comply with drug testing procedures outlined by the United States Anti Doping Agency (USADA) and requested by Mayweather's management to ensure fair play and sportsmanship by both fighters.

Richard Schaefer, CEO of Golden Boy Promotions, was contacted by Top Rank President Todd duBoef, who informed Schaefer that Pacquiao would not agree to have his blood taken within 30 days of the bout based on the fighter's superstition of testing so close to a fight.

“Todd told me that Pacquiao has difficulty with taking blood and doesn't want to do it so close to the fight,” Schaefer said in the statement. “He, Pacquiao, would only agree to have blood drawn before the kick-off press conference and after the fight.”

Olympic style drug testing involves random sampling of the athlete's blood and urine prior to and after the fight. The USADA procedure includes both blood and urine sampling so that all banned substances, some of which do not show up in urine alone, are tested for thoroughly.

“It is unfortunate to hear this from Manny Pacquiao's representatives, particularly since, as of today, both parties had worked out all other issues related to this fight,” said Schaefer. “Team Mayweather is certainly surprised that an elite athlete like Manny Pacquiao would refuse drug testing procedures which Floyd has already agreed to and have been agreed to by many other top athletes such as Lance Armstrong, and Olympians Michael Phelps, LeBron James and Kobe Bryant.”

Mayweather, who was informed of Pacquiao's reluctance shortly after Schaefer received word of the impasse, feels Pacquiao has to explain himself immediately or be faced with accusations from the media and the public regarding his own status as a clean and drug-free athlete.

“I understand Pacquiao not liking having his blood taken, because frankly I don't know anyone who really does,” said Mayweather. “But in a fight of this magnitude, I think it is our responsibility to subject ourselves to sportsmanship at the highest level. I have already agreed to the testing and it is a shame that he is not willing to do the same. It leaves me with great doubt as to the level of fairness I would be facing in the ring that night.

“I hope that this is either some miscommunication or that Manny will change his mind and step up and allow these tests, which were good enough for all these other great athletes, to be performed by USADA.”

No Top Rank officials were immediately available for comment.