Brock Lesnar, Samoa Joe, Roman Reigns and Braun Strowman will all be competing for the WWE Universal Championship in the main event of SummerSlam 2017. All four wrestlers seemingly have a realistic chance to leave Barclays Center on Aug. 20 with the top “Monday Night Raw” title.

Having won the belt from Goldberg at WrestleMania 33, Lesnar is the favorite in the upcoming match. Paddy Power gives him 4/9 betting odds to get the victory, though he’s far from a guarantee to retain.

READ: Ranking The WWE Universal Championship Contenders 

Samoa Joe is the second-most likely contender to win the WWE Universal Championship with 5/2 betting odds. He lost to Lesnar in a singles match for the title at Great Balls of Fire on July 23, but Joe put up such an impressive showing that he was given another shot at the belt.

Roman Reigns can never be counted out in a title match, though he isn’t among the favorites with 9/2 odds. The former Shield member hasn’t been a world champion since he was beaten clean for the WWE Championship by Seth Rollins at Money in the Bank 2016.

Strowman is the biggest longshot in the field, fighting for a world title for the first time in his WWE career. With 8/1 odds, he’s not expected to pin either Lesnar, Joe or Reigns.

Paul Heyman’s announcement regarding Lesnar’s future with the company might be among the biggest reasons why the current champion is expected to retain his belt. With three weeks remaining left until the pay-per-view, Heyman said Lesnar would leave the company if he loses his championship at SummerSlam.

Considering Lesnar is still under contract with WWE, and his deal reportedly runs through WrestleMania 34 in April of next year, it can be assumed that he won’t be exiting the company this summer. WWE might be trying to take advantage of the rumors that Lesnar could leave the pro wrestling business for a return to the UFC, specifically for a fight against Jon Jones.

Of course, WWE could always have Lesnar lose and still find a way around the stipulation at some point in the next few months. It’d be surprising for him not to have a match at both Royal Rumble 2018 and WrestleMania 34.

The 2018 Royal Rumble is still five months away, but there are already betting odds for WWE’s first big event of next year. Reigns and John Cena are tied as the favorites with 9/4 odds to win the 30-man battle royal and earn a world title shot at WrestleMania 34.

If the last few years are any indication, Reigns will be in the main event of WrestleMania 34. He’s competed in the final match in each of the last three WrestleManias, taking on Lesnar, Triple H and The Undertaker.

READ: Brock Lesnar, John Cena Highlight Updated SummerSlam Card 

Reigns will likely fight for the world title on April 8, 2018 in New Orleans. It’s just a matter of how he gets in the match.

Reigns could win the WWE Universal Championship and hold it until WrestleMania 34, where he’ll defend it against the Royal Rumble winner. If Reigns doesn’t get the victory at SummerSlam, there’s a good chance he’ll win the Royal Rumble in January.