With multiple records in boxing being broken already, Pacquiao doesn't have much left to prove to himself, the fans or the 90 million Filipino citizens he inspires everytime he fights. What does a win over Mosley really do for his career? We are interested because it's Pacquiao, but that doesn't mean that he is interested.
There is no doubt he is inspired and motivated to keep boxing, because it's what makes his country proud, but his long-term goals may be focused elsewhere.
When Manny Pacquiao started climbing the pound-for-pound rankings, he also started climbing up in weight.
He made the move from featherweight to lightweight, then to welterweight, all in a single year in 2008. He stayed at welterweight, where the opponents were bigger and stronger but not as fast.
If the added weight is not taking its toll, are the punches?
His last fight came against Mexican-boxer Antonio Margarito, who weighed 150 pounds; a total of 20 pounds heavier than his 2008 opponent Juan Manuel Marquez. Pacquiao took a total of 401 punches against hard-hitters Miguel Cotto and Margarito combined.
We don't see the physical toll it takes on "Pacman" because he doesn't show it, but it is there.
It may be because everyone wants to see Pacquiao fight Floyd Mayweather Jr., but his recent opponents haven't been the most popular. As long as fans want to see a good fight, they will tune in no matter who he is fighting.
Fights against Margarito, Joshua Clottey and Mosley are intriguing, but they don't do much for him. He was expected to not only beat but destroy each of them, and his fight with Mosley can only be a proving point if he knocks out the 39-year-old veteran within the 12-round distance.
There is only one thing driving the Filipino icon, and that's his nation's people.
When Pacquiao was elected to the House of Representatives in the 15th Congress of the Philippines in 2010, it was one of the biggest achievements he could have dreamed of. His aspirations in the courtroom were starting to grow more than they were in the boxing ring.
He had ran before but came up short against Darlene Antonio-Custodio. The Filipino people were not ready to see Pacquiao being involved in the political movement in 2007, but they were in 2010 and elected him by twice as many votes as his opponent.
Pacquiao knows what it's like to not have the congressman not watching over him and looking out for what's best. He had lived much of his life sleeping on dirt floors and living in poverty, as many Filipino children do. When he became elected, he now has the chance to change this type of lifestyle for the millions of children who struggle to survive.
His boxing achievements may inspire the children to rise up and fight for their country, but it's in his political career where the real work gets done.
The 32-year-old has no intentions of fighting past 35, and he probably won't if he continues to walk through his opponents.
This could be cut short if he doesn't get the fight with Floyd Mayweather Jr. If he never does get that fight, he can't possibly have anything more to prove.
There have been negotiations of him fighting Juan Manuel Marquez for a third time, but he doesn't seem to interested in that. He had beaten the Mexican boxer in their rematch by split-decision.
Wins over Oscar De La Hoya, Ricky Hatton, Marco Antonio Barrera, Erik Morales and Miguel Cotto highlight his career of dominance and desperation to be the best boxer in the world.
He was 2000's "Fighter of the Decade." How could he top that? He would have to continue fighting for the good first half or more of 2010-2020 and even then, risk losing at an age where his skills will start to decline.
This may not be his last fight but if it is, it wouldn't hurt the legacy he had already built.
If "Sugar" Shane Mosley does manage to pull off the upset victory over Pacquiao, it could be the very last time we see both inside the ring.
Pacquiao has beaten the very best of his generation, except for Mayweather Jr., and Mosley just recently lost a dominant 12-round unanimous decision to "Money" last May.
A loss may actually be enough to get Mayweather to fight Pacquiao, but would he want it if he loses? It could be a big "YES" or a big "NO."
Mosley, a 4-1 underdog, has a small chance of upsetting the Filipino superstar. He is far beyond his prime, but still possesses knockout power. His 72 percent knockout percentage can attest to that.