The potential bouts for the top welterweights in boxing got turned upside down after the last major fight that ended rather controversially.

Though Filipino icon Manny Pacquiao kept his title belt in a contentious majority decision over Juan Manuel Marquez, there are questions surrounding who the next opponent will be for each prize fighter.

Pacquiao was seeking a knockout win over Marquez and didn't come close to pulling it off. In some minds, Marquez deserved the victory over the current Philippines' congressman, but round-by-round, the fight seemed almost too close to call.

Aside from the debate of which boxer deserved the win, Marquez may feel that he has to move on from Pacquiao. In three hard-fought bouts, the best result the 38-year-old Mexican has earned was a draw.

The dilemma is that both boxers may not have better options than to fight each other once again.

According to Pacquiao trainer Freddie Roach, a fourth fight between Marquez and Pacquiao should be next.

It was a very close fight, said Roach. We were able to squeeze it out. I thought the fight was very close but Manny pulled out those last two rounds.  Marquez stayed in counter-punching mode and when the rounds are close I will go with the aggressor. ... I think Marquez deserves a rematch. The fight was close. I think all of their fights will be close. Marquez fought very well.

Floyd Mayweather Jr., who knocked out Victor Ortiz in a rather controversial bout in September, has a May 5 reservation at the MGM Grand, but doesn't have an opponent. Mayweather dominated Marquez in 2009, so a rematch is unlikely.

A Mayweather-Pacquiao fight is what the public wants, but there has been a great deal of back-and-forth between the two camps. Some believe there is little chance of the fight taking place, as questions surrounding drug testing has held up the megabout.

It'll never happen, famed boxing expert and historian Bert Sugar told International Business Times, in an exclusive interview. I said it two and a half years ago, and for two and a half years I've been right, and I will stay right.

Sugar believes that Mayweather is too proud of his undefeated record to risk it against a Pacquiao fight, and has used drug testing as a way to stall the fight.

Mayweather isn't afraid of Pacquiao, mind you, he's afraid of losing, said Sugar.

Prior to the Pacquiao-Marquez bout, Sugar listed Pacquiao as six-to-five favorite over Mayweather.

After the result of Pacquiao-Marquez bout, perhaps Mayweather may believe that his undefeated record might come down to judges who would favor Pacquiao in a 12-round decision. His recent comments may have provided that indication.

I truly feel that Marquez is never going to get the benefit of the doubt, said Mayweather, in an interview with FightHype. I want to congratulate Marquez and I want to congratulate Manny Pacquiao for doing it a third time, but I just feel like if you get it done right the first time, there's no need for a second or third fight. And if it is needed, do it again in the same fashion and in the same way, or do it even better. 

Though he has 42 fights without a loss, Mayweather has been tested in his career. He defeated Oscar De La Hoya in a split decision in 2007, and had two hard-fought bouts with Jose Luis Castillo in 2002.

There is a great deal of money on the table for both Mayweather and Pacquiao should the fight take place. With both boxers perhaps receiving $50 million, it seems plausible that the fight will eventually happen, but the question is when.

Mayweather is 34, and Pacquiao is nearing his 33rd birthday. Both fighters may not have many fights left, especially for Pacquiao who has his congressman duties in the Philippines and his singing aspirations.

Other boxers who are certainly in the mix to fight Pacquiao, Mayweather, and Marquez include Amir Khan and Timothy Bradley. Khan and Bradley are in their 20s, and are viewed as burgeoning boxing talents that deserve a major bout. Bradley easily defeated Joel Casamayor on Saturday, and Khan has a fight with Lamont Peterson in December.

A boxer who might complicate things is Sergio Martinez. The middleweight champ is considered one of the best pound-for-pound boxers but might have to agree to a same-day weigh-in at 150 pounds if he expects to fight someone like Pacquiao. That may be hard to pull off, as it uncustomary practice in contemporary boxing. Also, the weight fluctuations of Martinez and his opponent would make for perhaps an uneven result.

The coming weeks will offer a glimpse of what's to come from the most exciting division of boxing.