Manny Pacquiao could face prosecution for perjury after failing to reveal shoulder injury ahead of Floyd Mayweather fight

Manny Pacquiao faces a potential lawsuit after failing to disclose a shoulder injury before his defeat by Floyd Mayweather.

Pacquiao will spend up to a year on the sidelines as he prepares to undergo surgery on his torn rotator cuff, an injury he suffered in training.

But the Filipino star could also be guilty of perjury after signing a pre-fight questionnaire without revealing he was hurt.

Sportsmail has obtained a copy of the document and although it shows that Pacquiao was taking several painkillers, the word ‘No’ is marked next to the question: ‘Have you had any injury to your shoulders, elbows, or hands that needed evaluation or examination?’

By signing the document, both Pacquiao and his adviser Michael Koncz ‘hereby swear under penalty of perjury, that the above information is true and correct to the best of my knowledge’.

Under chapter 199 of the law of Nevada (NRS), ‘A person who, in a declaration made under penalty of perjury, makes a wilful and false statement in a matter material to the issue or point in question is guilty of perjury or subornation of perjury, as the case may be, which is a category D felony and shall be punished.’

The punishment for a crime of this nature is between one and four years in prison and a fine of up to $5,000 (£3,305).

Pacquiao could also be fined or banned by the Nevada State Athletic Commission.

The commission' chairman Francisco Aguilar said that the state attorney general's office will look at why the injury was not declared.

'We will gather all the facts and follow the circumstances,' he said. 'At some point we will have some discussion. As a licensee of the commission you want to make sure fighters are giving you up-to-date information.

‘The medications he was taking were disclosed on his medical questionnaire, but not the actual injury.

'This isn't our first fight. This is our business. There is a process, and when you try to screw with the process, it's not going to work for you.'

Koncz told the New York Times 'Number one, Manny didn't check the box. I checked it. It was just an inadvertent mistake. If I was trying to hide anything, would I have listed all the medications on the sheet that he intended to use? We weren't trying to hide anything. I just don't think I read the questionnaire correctly. see below document after this cut....

'I’m going to take full responsibility for what happened. The wrong box was checked. But I think part of the responsibility also lies with the commission. Wouldn't you ask a question about all these medications (on the questionnaire)?

'The bottom line is that we weren't trying to hide anything. If we had wanted to, we could have done the injection at the hotel before the fight and nobody would have known but we didn't want to hide anything.'

The 36-year-old's physician, Dr Neal ElAttrache told ESPN.com: 'Once you know he has a tear that's not going to heal on its own, then the decision for an active person is you want to try to fix this before it gets bigger.

'If all goes as expected with the surgery and the rehab is successful, Manny could be back training in about six months.

'At that point, he will be regaining strength and endurance, and competition is reasonable within nine months to a year. But this is a severe enough tear that it won't heal without being repaired.'

Earlier on Monday, his team expressed their disappointment that the boxer was not allowed to continue his treatment in the dressing room.

A joint statement issued by promoters Top Rank Boxing read: 'During training, Manny Pacquiao suffered a right shoulder injury.

'Manny went to see world-class doctors, partners in the prestigious Kerlan Jobe Orthopedic Clinic, who performed tests and, in consultation with Manny, his promoter, and his advisors, concluded that with short rest, treatments, and close monitoring, Manny could train and, on May 2, step into the ring against Floyd Mayweather.

'Manny's advisors notified the United States Anti-Doping Agency (USADA) of the shoulder injury and the treatments being proposed by the doctors during training and on fight night.

'USADA spoke to Manny's doctors twice, investigated, and confirmed in writing that the proposed treatments, if used, were completely allowed. The medication approved for fight night was a non-steroidal anti-inflammatory (Toradol).

'Manny continued to train and his shoulder improved, though not 100 per cent. This is boxing, injuries happen, and Manny is a warrior.

'Again, in consultation with his doctors, promoter and advisors, Manny decided to proceed with the fight anticipating that he could receive his pre-fight treatment. That specific treatment had been approved by USADA in writing at least five days before the fight.

'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.

'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.

'Also, USADA had provided a copy of its contract with the fighters to the Commission. An hour before the fight, Manny's advisors asked the Commission to reconsider and the director of USADA advised the Commission that USADA had approved the fight-night treatment, but the Commission denied the request.

'With the advice of his doctors, Manny still decided to proceed with the fight. His shoulder wasn't perfect but it had improved in training camp.

'However, as Manny has said multiple times, he makes no excuses. Manny gave it his best.'

But USADA's Travis Tygart said the agency was ‘only a third party to the fight, charged only with testing the fighters for banned substances in training and the night of the bout.’

He said they had no medical information or any copy of an MRI scan or other documents.

‘It was not an anti-doping issue,’ Tygart told AP. ‘The real question is why his camp checked 'no' on the disclosure.

‘Either they made a terrible mistake not to follow the rules, or they were trying not to give information to the other side. I'm not sure there's a middle ground.’