The Rock
The Rock can't be ruled out as a potential opponent for Brock Lesnar at WrestleMania 31. Reuters

Five WWE pay-per-views remain until WrestleMania 31, but it’s difficult not to look ahead to the big event. Brock Lesnar has been the WWE World Heavyweight Champion for two months, and all signs point to him holding onto the belt until the biggest PPV of 2015.

Lesnar hasn’t been on “Monday Night Raw,” since he retained the title at Night of Champions, and his part-time status could keep him off WWE TV for quite some time. It appears that the plan is for him to be the champ until WrestleMania 31, where he will drop the belt.

Since his win over The Undertaker at WrestleMania 30, Lesnar has been an unstoppable force in WWE, winning the title off John Cena at Summerslam in one of the most one-sided PPV matches in recent memory. Therefore, WWE will be very selective in choosing the wrestler that finally puts an end to Lesnar’s title reign.

What WWE wrestler will beat Lesnar at WrestleMania 31? Below is a look at the five most likely candidates.

Daniel Bryan

After an injury forced Bryan to hand over the WWE World Heavyweight Championship in June, WWE is in a perfect position to set up Bryan vs. Lesnar at WrestleMania 31. There’s a good chance that Bryan will make his return at the 2015 Royal Rumble, allowing him to leave the PPV victorious and challenge for the title. Bryan has shown that he has what it takes to be the company’s No.1 babyface, though WWE might want to use Lesnar’s WrestleMania match as an opportunity to elevate a younger wrestler into superstar status.

Roman Reigns

When Lesnar won the WWE World Heavyweight Championship at SummerSlam, it appeared that he was on a collision course to face Reigns at WrestleMania 31. Reigns remains the favorite to take the title off Lesnar, becoming WWE’s next big star in the process, but recent events could force the company to change its plans. His recent injury could keep him out for a few more months, and he has yet to prove that he has the mic skills to be a main event superstar. Still, the former Shield member is a big part of WWE's future, and winning the title over Lesnar could cement him as the company's next top star.

The Rock

Plans for The Rock vs. Brock Lesnar at WrestleMania 30 fell through because of an injury to The Rock, but that doesn’t mean the two superstars won’t face off on wrestling’s biggest stage. In the summer, a rumor circulated the internet that Vince McMahon wanted the match to happen at WrestleMania 31, and The Rock is just about the biggest draw that WWE could get for the event. His movie career might keep him out of the ring, and he recently told TMZ that he doesn’t expect to wrestle in April, but it’s an option that WWE might consider.

Dean Ambrose

If the internet wrestling community had its way, the former Shield member would likely be in the main event of WrestleMania 31. WWE might not currently foresee Ambrose being the next face of the company, but they could be forced to consider him if his popularity continues to grow. With Bryan injured and CM Punk gone, Ambrose trails only John Cena as the top babyface on WWE TV. He and Paul Heyman could trade some memorable promos if WWE were to give Ambrose a shot at the title, and a large portion of the fanbase would embrace it with open arms.

John Cena

Considering Cena had Lesnar beat at Night of Champions before Seth Rollins interfered, it appeared that WWE was setting up another match between the two wrestlers. The latest rumors have the last two champions squaring off at the Royal Rumble, but WWE could move the match to WrestleMania if it decides that Reigns isn’t ready. Cena vs. Lesnar at Summerslam was highly anticipated, and Cena can never be counted out of the main-event picture.