Mayweather vs Pacquiao rematch? Filipino's shoulder surgery could determine

 Manny Pacquiao (L), Floyd Mayweather (R) before match Photo: Courtesy

Manny Pacquiao is set to undergo shoulder surgery - which could keep him out of the ring for 9-12 months and scupper any chance of a rematch with Floyd Mayweather.

Pacquiao was beaten on points by the American in Las Vegas on Saturday, and complained of an injury in the aftermath of the bout.

The richest fight in boxing history didn't quite live up to the hype, as Mayweather produced a defensive masterclass to take the victory by a unanimous decision.

The undefeated Mayweather says he will fight once more before hanging up his gloves, and a rematch with the Filipino had been touted, but surgery on his torn rotator cuff would likely scupper those hopes.

“We have an MRI scan that confirms he has a rotator cuff tear. He has a significant tear,” orthopedic surgeon Neal ElAttrache told ESPN.com.

The developments could open the door for Amir Khan to fight Mayweather in Las Vegas, to try and inflict Money's first defeat in his professional career.

Floyd Mayweather senior has talked up the potential fight - because he thinks it would be an easy victory for his son to bow out with.

He said: “I’ll tell you what I think my son should do in September – given he’s fought all the hard-hitters – my son needs to get his contract and end it with an easy fight, he don’t need no tough fights.

“Amir Khan? Yes, that’d be a good fight for him. My son would beat him, I know. Of course it would be easier than Pacquiao. Khan has a pretty decent jab but all the technical things; he can’t do [them].”

However, Khan's reluctance to fight in September due to Ramadhan could be a stumbling block.

Khan said: “I think Mayweather’s team wants the fight. I really believe I have Mayweather’s number.

"I am ready for whatever he wants. I can’t do September because of Ramadhan but if we can do this year or early next year, I will definitely jump to it.”