And his trainer Freddie Roach said they did at one point consider postponing the fight.
Pacquiao was comprehensively beaten on points by Mayweather in Las Vegas, the unbeaten American too fast, too slick, and too accurate for him.
The judges scored it 118-110, 116-112 and 116-112 in Mayweather???s favour. Pacquiao had his moments but Mayweather always managed to get out of trouble when he needed to.
In his post-fight press conference however, Pacquiao revealed that he had been troubled by a right shoulder injury in the weeks leading up to the fight,
???Three weeks before my fight I had to skip my training for a couple of days for that reason. We went for an MRI ??? there is a tear in my right shoulder,??? he said.
And he revealed that despite the injury improving in the run-up to the Vegas showdown, it affected his tactics. ??
???I cannot use my right shoulder a lot. The fight was still good. But what we wanted to do, we could not do because of my shoulder.
???The thing is in the third round I already felt the pain in my shoulder. When I threw a lot of combinations I had to back off because it hurt.
???But he???s fast ??? he???s a good boxer. Give credit to him ??? he won tonight.???
Roach confirmed that postponing the fight was considered at one point.??
???It was getting better and better every day but we thought about, one time, postponing the fight,??? he said.
???As the weeks went on it was getting better. He was feeling really good in the gym and I was happy with his performance. He was doing a lot better in sparring.
???I figured he could get through the fight. I???d never want to put a fighter into a fight injured that badly. But I thought the progress was good enough. That???s why we stayed with the fight.???
Pacquiao???s long-time promoter Bob Arum said: ???Apparently, the doctors say it was an old injury. There are four something-or-others (in the shoulder). Two were not operable, two were ok. (NBA star) Kobe Bryant has had the same thing.