Floyd Mayweather Jr. is fighting September 12 against Andre Berto in a match that he's proclaimed will be his last. Freddie Roach, the trainer of Manny Pacquiao, does not buy it.

"I don't think he'll stop at 49 fights, I think he'll fight to 50. I'm hoping that he promotes himself, maybe if he does he can make more money," Roach told Boxing News.

If Mayweather beats Andre Berto -- which he is a massive favorite to do -- he will boost his record to 49-0, which would tie the great Rocky Marciano's undefeated record. Mayweather is most likely capable of fighting beyond this September, but he recently cited his uncle Roger Mayweather's worsening health as a motivation to hang the gloves up.

"My uncle Roger Mayweather has lost a lot of memory from the sport of boxing," Mayweather told Fight Hype. "It's sad that he's only in his 50s, but he seems like an old man that's in his 80s."

Mayweather gave examples of his uncle's deterioration, mentioning that Roger walked home from the MGM Grand the day before the Pacquiao fight. Floyd Mayweather estimated the distance to be about 20 miles.

Mayweather's record paydays may offset the risk to return to the ring though, especially with Mayweather's superior conditioning and ability to avoid taking major punishment in his fights. His upcoming fight vs. Berto has been roundly criticized as a mismatch, but already there are seeds of a possible rematch vs. Pacquiao.

"Manny would do much better in a rematch, if the shoulder gets better," Roach said. "We were doing well until the shoulder went in the fourth round and we had a tough time after that. I do think we can beat Mayweather 100 percent." After his unanimous decision loss, Pacquiao revealed he was fighting with a torn labrum.

For now, all anyone can do is take Mayweather at his word, even if he has ended one retirement already.

"September 12th is my last dance," Mayweather said. "On September 13 I just want to sit back and watch some football."

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