Manny Pacquiao is 2-0-1 against the legendary Juan Manuel Marquez and many fans feel he should be 0-3. Most recently, Pacquiao struggled his way through a November 12 clash that many felt he would dominate, instead escaping with a win over Marquez that had many seriously reevaluating their opinion of how a Pacquaio vs. Floyd Mayweather fight would look. Of course, we've since heard that Manny underestimated Marquez, or maybe his calves were cramping again (a Manny fallback when things get tough, it seems), or maybe it was problems with his marriage, or maybe his focus wasn't there because of his duties as a congressman.
Marquez wants a fourth shot at Pacquiao and he will now be at ringside for Saturday's clash between Manny and Tim Bradley.
If Pacquiao does beat Bradley, Marquez would seem the most logical next opponent. There just aren't that many guys out there to fight at the weight Pacquiao wants, who aren't affiliated with Golden Boy. (GBP and Top Rank might work together for some lesser fights, but I don't think Manny's close to fighting Victor Ortiz or anything like that.)
Bradley is coming up in weight for this fight, and should he drop back down to junior welterweight after the bout, Marquez is the mandatory challenger for Tim's WBO title. So he really has an interest in both fighters.
Even should Manny lose, that doesn't eliminate the chances of a fourth Marquez fight, although it'd be much more likely that we just get a Pacquiao vs. Bradley rematch first. And with Marquez's age and the miles on his body, every delay in getting his last crack at Manny is damaging.