Floyd Mayweather has one fight left on his contract with Showtime and has said multiple times that he plans on fighting his 49th professional bout in September 2015.

But, against whom?

Mayweather is now 48-0 after his victory against Manny Pacquiao, which didn't exactly live up to the huge six-year expectations. So many different names have been rumored as possible challengers for Mayweather in 2015, but nothing has been confirmed yet.

The odds of Mayweather facing Pacquiao in a rematch are very unlikely. Pacquiao has undergone shoulder surgery, which will keep him out for another nine to 12 months. For Mayweather to wait another year for this potential fight is extremely risky. Pacquiao may not be ready next year, and that would be a huge waste of time for Mayweather.

After that, the field is still pretty big. The biggest name being rumored around a possible Mayweather fight is Amir Khan. Khan still has to face Chris Algieri on May 29. However, there is also a religious factor that may interrupt this fight. Khan celebrates Ramadan and has to fast. The last time Khan fought in September, he was knocked out in the first round by Breidis Prescott.

Another potential fighter who is rising up the ranks is Keith Thurman. "One Time" is currently ranked No. 3 in the Welterweight rankings behind only Mayweather and Pacquiao, and considering Pacquiao is out for a year, it would only make sense to face Thurman next. Thurman is young, energetic, powerful and he deserves this fight. A Thurman vs. Mayweather match would be a classic matchup of speed against power with two types of schools going at it.

There honestly shouldn't be any reason against a Thurman vs. Mayweather fight this September.

The biggest name gaining attention recently has been Gennady Golovkin. Golovkin is a perfect 33-0 in his career with 30 knockouts. "Triple G" is also the No. 1 ranked middleweight fighter in boxing today. A Golovkin vs. Mayweather fight promises to be entertaining, but it would be very complicated. The two champions each fight in two separate weight divisions, so someone will have to gain or lose weight for this potential matchup.

Timothy Bradley would make for an interesting fight against Mayweather; however, that would also be very complicated. Bradley is signed with Top Rank, whereas Mayweather is with Showtime. The Mayweather-Pacquiao fight took long enough to occur mainly because of contract negotiations. Bradley and Mayweather are similar type of boxers, and it would make for an interesting fight. But again, it probably won't happen because of contract details.

One other name that has been floating around has been Kell Brook. Brook will fight Frankie Gavin on May 30, but he could be a possible Mayweather opponent for September. He is a perfect 34-0 in his career thus far, and a win over Mayweather would do wonders for his legacy. For Mayweather, this fight wouldn't exactly bring in the highest revenue when compared to Thurman or Golovkin.

Other potential welterweight fighters include Shawn Porter, Brandon Rios, Robert Guerrero and Devon Alexander.

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