Floyd Mayweather Jr. has been teasing about a possible fight on September of this year, the only question remaining is who should he face next.

The pound-for-pound best boxer in the world is on a 48-fight unbeaten streak with his latest victory, a unanimous decision nod over Filipino boxer Manny Pacquiao.

He currently holds the WBC, WBA, WBO and Ring welterweight championship, and the WBC Super, WBA and Ring junior middleweight title.

However, at 38 years old, the window for Mayweather is slowly closing and with emerging stars coming up within the ranks, there is a list of fighters that he could face next.

One who many people consider should be his next challenge is Amir Khan. The British professional currently holds the WBC Silver Welterweight title and sports a 31-3 record.

He currently is on a five-fight win streak, with wins over Julio Diaz, Devon Alexander and Chris Algieri.

Khan has always wanted a fight against Mayweather and believes that the Mayweather camp is worried and will not fight him for the challenges he gives. He is much bigger and has a significant advantage in length and is still hitting his prime at 28 years old.

Meanwhile, another challenger in the mix is Andre Berto. The 31-year-old has a 30-3 record with 23 wins by way of knockout or TKO.

He has won his last two bouts, beating Steve Upsher Chambers and Josesito Lopez and despite not having as much accolades as Khan, he still possesses knockout power that can upset Mayweather.

Finally, and the least likely, is Timothy Bradley. Nicknamed Desert Storm, he has a 32-1 record, with his only professional loss coming from Pacquiao.

His big-named wins have come from Pacquiao (in a controversial manner), Ruslan Provodnikov and Juan Manuel Marquez.

However, his latest win against Jessie Vargas came in another controversial decision as the referee prematurely stopped the fight with still ample time left in the final round.

Bradley was winning the fight on the scorecards but was visibly staggered by Vargas' assault at the tail end of the 12^th round.

The referee mistakenly pulled the fighters off with time remaining, thinking that the match was over. However, the move only allowed Bradley to recover and eventually get the unanimous decision win.

These are some of the fights that Mayweather may have on the table, the only question is -- which boxer will he choose to fight against?