(SportsNetwork.com) - Manny Pacquiao was denied treatment for his right shoulder prior to Saturday's fight against Floyd Mayweather, an injury which will reportedly require surgery.

Top Rank issued a statement late Monday, saying it had approval from the United States Anti-Doping Agency (USADA) for treatment on a shoulder injury Pacquiao had suffered while training for the welterweight unification bout in Las Vegas, but the Nevada Athletic Commission prevented it Saturday night because it was not notified of any injury.

"On his pre-fight medical form filled out earlier in the week, Manny's advisors listed the medications that Manny used in training and the medications that might be used on fight night," the statement read. "A few hours before he was expected to step in the ring, when Manny's doctors began the process, the Nevada Commission stopped the treatment because it said it was unaware of Manny's shoulder injury.

"This was disappointing to Team Pacquiao since they had disclosed the injury and treatment to USADA, USADA approved the treatments, and Manny had listed the medication on his pre-fight medical form."

However, the New York Daily News reported Tuesday that a member of Pacquiao's camp checked a box "no" for a question regarding possible injuries on the medical form.

If so, the News reported, the state of Nevada could start an investigation since the signed document comes under the penalty of perjury.

Top Rank's statement Monday said Pacquiao underwent tests with the Kerlan Jobe Orthopedic Clinic after the shoulder injury was discovered a few weeks before the fight. It apparently wasn't serious enough to warrant a postponement of the highly anticipated bout because treatment and rest allowed for Pacquiao to continue training.

However, ESPN has reported that Pacquiao will now undergo surgery for a torn rotator cuff in the shoulder later this week.

Pacquiao lost a unanimous decision Saturday night and disclosed his injury only in the post-fight press conference. His camp said the injury had progressed in the days leading up to the fight and it only worsened after the third round on Saturday.

"His shoulder wasn't perfect," Top Rank said, "but it had improved in training camp. However, as Manny has said multiple times, he makes no excuses. Manny gave it his best."