The WBA Welterweight Champion of the world, Floyd Mayweather Jr., spent his 2014 campaign fighting Marcos Maidana twice. As we all know, Mayweather defeated Maidana both times convincingly.

Boxing fans know that Mayweather is the undefeated champion, but many still feel as if he isn't facing tough competition. For Mayweather to prove his doubters wrong, he will have to face tougher opponents in 2015.

Here are five boxers Mayweather could face next year.

1. Manny Pacquiao

This is the fight that everyone wants to see. A match with the 35-year-old Filipino would be Mayweather's toughest fight yet. We've seen the two argue on social media platforms such as Instagram but never in the ring. The two just can't seem to agree on a money split, fight location, drug testing or even a rematch clause in the potential contract. A fight with Pacquiao would gross an estimated $300 million, but "Money" Mayweather still hasn't agreed to fight Pacquiao. Many trainers and boxing experts believe Mayweather is worried about Pacquiao's southpaw fighting style.

2. Timothy Bradley

It wouldn't be Mayweather vs. Pacquiao, but this would definitely make an interesting match. Timothy Bradley is 31-1 in his career so far with a loss to Pacquiao back in April. Bradley would be a much better opponent for fans to watch than Maidana. The 31-year-old Bradley has great speed and athleticism, but his knockout power is pretty limited. In a lot of ways, he's comparable to Mayweather but not as good. Bradley is currently ranked third in the welterweight division with a notable win over Juan Manuel Márquez and a controversial victory over Pacquiao.

3. Keith Thurman

What a fight this would be. Keith Thurman is without a doubt the most underrated boxer today with a perfect 23-0 record and 21 knockouts. Thurman isn't the second coming of Mike Tyson, but he is the best knockout artist in the welterweight division today. If (highly unlikely) this fight did happen, it would be a classic duel of power against speed. Would Thurman be able to connect with his powerful right hook? Would Mayweather be able to avoid Thurman for 12 rounds? It would make for a great fight, but only Mayweather can make the final call.

4. Amir Khan

Most likely this is who Mayweather will be facing in 2015. Amir Khan is an average boxer with good speed and intangibles, but he wouldn't stand a chance against Mayweather one on one. Khan has lost two of his last five fights, and he really doesn't have a lot of notable victories on his resumé. Although Khan is not an elite boxer, he would love nothing more than to face Mayweather. A fight with Mayweather would bring him more money than he's ever made before, win or lose. As for Mayweather, this would be Maidana all over again -- an easy fight with a large split.

5. Chris Algieri

Mayweather may not fight Pacquiao, but he could face the man who Pacquiao just beat. Chris Algieri is 20-1 with eight career knockouts. The 30-year-old out of Long Island has a long reach that may give Mayweather some problems. It's unlikely he would defeat Mayweather, but his resilience could set up for a good fight. Algieri is currently ranked No. 4 in the Junior Welterweight division, and he doesn't have a fight scheduled for 2015 yet.

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