Roman Reigns WWE
The main event of every WWE PPV in 2015 has featured a member of The Shield. Getty

The Undertaker and Brock Lesnar will fight in the main event of SummerSlam 2015, while John Cena is likely to face Seth Rollins with both the WWE World Heavyweight Championship and United States Championship on the line. Those two matches will be the biggest on the card, but other top wrestlers are still looking for something to do on Aug. 23 at Barclays Center.

Cena, Lesnar and Rollins have been the last three superstars to hold WWE’s top title, but a few other wrestlers have been a major part of the main-event scene in 2015. Randy Orton, Roman Reigns and Dean Ambrose have all fought for the WWE World Heavyweight Championship more than once this year.

Orton might not be involved in the title picture for a while, and he’s moved on to a feud with Sheamus. Orton got a clean victory over this year’s Money in the Bank Winner at WWE Battleground, and it’s looking more and more like they’ll have a rematch at SummerSlam. Since the last pay-per-view, they’ve been pitted against each other in multiple six-man tag matches on “Monday Night Raw.”

The team of Orton, Reigns and Ambrose defeated Bray Wyatt, Luke Harper and Sheamus on Monday, Aug. 3. While Orton is headed towards a singles match at the year’s second biggest PPV, Reigns and Ambrose look like they’ll be fighting together in Brooklyn.

More than 14 months after The Shield broke up, Reigns and Ambrose continue to team up. The Lunatic Fringe didn’t have a match at WWE Battleground, but Reigns lost to Wyatt in a singles match. Harper attacked Reigns and helped Wyatt win, setting up a potential tag team match at SummerSlam.

It looks like Reigns and Ambrose will face Wyatt and Harper in a few weeks. There had been rumors that Sting might get involved, joining the former Shield members against the heels. But Erick Rowan suffered an injury, preventing a reunion of The Wyatt Family from happening. It’s possible that a different wrestler could join Wyatt and Harper, opening the possibility for Sting to become a part of the match, but that doesn’t appear likely.

Other matches on the undercard are likely to include Kevin Owens vs. Cesaro and a retuning Dolph Ziggler vs. Rusev. Lana and Summer Rae have been involved in the feud between Ziggler and Rusev, and they should be a part of the match in some fashion.

Ryback has said that he’ll be healthy enough to have a match at SummerSlam after missing Battleground with a staph infection. He could defend his Intercontinental Championship against Big Show and The Miz.

The Prime Time Players will probably defend their titles against a few different tag teams. There could be two Divas matches on the card, and Nikki Bella might have to defend her championship against a wrestler that was recently called up from NXT.

Since SummerSlam has been extended to four hours, it will include more matches than other PPV's, other than WrestleMania.