WWE World Heavyweight Champion Brock Lesnar will put his title on the line against Roman Reigns in the main event of WrestleMania 31. Whether or not Lesnar retains the belt might be dependent upon his contract status with the company.

Lesnar’s contract is reportedly set to end after WrestleMania 31. WWE and Lesnar have engaged in negotiations regarding a new deal, but there have been conflicting reports surrounding those talks.

For months, there have been rumors that Lesnar has had an eye on making a return to UFC. He fought in UFC for four and a half years, winning the heavyweight title on Nov. 15, 2008. His last bout with the company came on Dec. 30, 2011, and though he’s spent the last three years with WWE, the champ could head back inside the octagon. He left UFC amid health issues, but he might be ready to compete in mixed martial arts, once again. Lesnar attended UFC 184 on Feb. 28, and UFC president Dana White said the two would likely talk when the WWE champion's contract comes to an end.

Towards the end of 2014, it appeared that WWE might be preparing to lose Lesnar and have him drop the belt to Reigns at WrestleMania 31. On the Feb. 23 edition of “Monday Night Raw,” Lesnar did not appear on the show after reportedly getting angry and walking out before the program ended. But it seems WWE does have a chance to sign the 37-year-old.

According to The Wrestling Observer, Lesnar’s future remains up in the air, but the company is still looking to keep him. Negotiations will continue on Monday, the date of the final episode of “Raw,” before WrestleMania 31.

If Lesnar and WWE do come to an agreement, it would likely increase the chances of Lesnar keeping the belt at WrestleMania 31. Since ending The Undertaker’s undefeated WrestleMania streak last year, Lesnar has become an even bigger star. His matches at 2014 SummerSlam and the 2015 Royal Rumble were two of the best in recent WWE history, and he’s become one of the most popular wrestlers in the company, possibly setting himself up for a future run as a babyface.

Even if Lesnar does come back, Reigns might still be the favorite to win the WWE World Heavyweight Championship. WWE has given the former Shield member a strong push over the last year, and he could eventually replace John Cena as the company’s top star.

The biggest question surrounding the WrestleMania 31 main event has been how the crowd might react, considering fan favorite Daniel Bryan won’t be in the match. But the winner of the match, which once seemed to be a foregone conclusion, is no longer a guarantee.