The worst-kept secret in professional wrestling for the past few years has been that Roman Reigns vs. The Rock will headline WrestleMania 39 when WWE comes to Hollywood.

Barring any scheduling conflicts or injuries, that will be the main event of the second night of the marquee pay-per-view and is likely the only thing set in stone at the moment.

However, there is still one other night that needs a main event and anything can happen before next April.

Ignoring Reigns and The Rock, who else could realistically be in the running to check "WrestleMania main eventer" off their list?

Let's break down the most likely options to watch out for in the coming months.

Cody Rhodes and Seth Rollins

There is no telling when Cody Rhodes will be ready to return to in-ring action. When that does happen, though, the best thing he could do would be to win the men's Royal Rumble match and challenge for a world title.

That has been his purpose since coming back to WWE, and it's a story that needs to be told.

The only roadblock is that Reigns is holding both world titles and seems poised for that match with The Rock, rather than The American Nightmare.

Theoretically, though, something could happen in the meantime that forces a split of the titles.

When Rhodes returns from injury, he will likely fight Seth Rollins to get back at him for how their feud ended. And if The Visionary has won the WWE belt from Reigns before then, that could set up a title shot for the former All Elite Wrestling star.

Even if a title isn't on the line, WWE could consider Rhodes vs. Rollins to be a big enough match to justify headlining the first night of 'Mania.

John Cena and Austin Theory

Don't bet the house on it, but another potential title change that could happen before WrestleMania 39 is Austin Theory cashing in his Money in the Bank contract to take one or both belts away from Reigns.

If that happens, the 25-year-old instantly jumps to the front of the pack to headline The Show of Shows, particularly if WWE can get John Cena to wrestle on the show.

Since Theory has been touted as "the next Cena," there is no better opponent for him.

Even better, part of the story would be Cena attempting to surpass Ric Flair's record of 16 world titles. So, either Theory beats the person he's living in the shadow of or Cena wins his 17th belt. Either scenario is worth getting invested in for a main event.

Brock Lesnar

It seemed Brock Lesnar had wrestled his send-off match at WrestleMania 38. Then, a few weeks later, he was back for another so-called final match against Reigns.

Never say never in wrestling. Wrestlers can have multiple retirements and there is always a chance with the right money and idea that they can step inside the ring again.

The Beast Incarnate is on a different level than nearly any other Superstar in WWE history. He could have a match against anyone and WWE would instantly consider it a main event.

Whether this would be another fight with Bobby Lashley, a new feud we haven't seen yet or even a retirement match, don't count out Lesnar appearing and adding a sixth WrestleMania main event to his name.

The Rated-R Superstar Edge

In a similar vein, Edge isn't going to be wrestling for another 10 years. He's going to hang up the boots sooner or later, and told fans in attendance on the August 22 episode of Raw that perhaps next year would be when he says goodbye.

Who's to say The Rated-R Superstar doesn't have one more main event in him that gets approved as the final match of the first night?

The 48-year-old did win the men's Royal Rumble in 2021 to go on to fight Reigns and Daniel Bryan in the main event of WrestleMania 37. Don't discount him just because people in his position usually wrestle elsewhere on the card in a marquee upper-midcard match.

It would depend on a lot of factors, but Edge has done it before and can do it again.

Raw and SmackDown Women's Championship Contenders

Up until WrestleMania 35, no women's match had been the main event of the show. Since then, Bianca Belair and Sasha Banks have also headlined WrestleMania 37.

Nothing is stopping WWE from having the first night of WrestleMania 39 follow suit, with either the Raw or SmackDown Women's Championship on the line.

Since we don't even know who will be holding the titles next April, it's hard to pinpoint two names as the go-to women to fill this role. However, we can still narrow it down to a handful of figures most likely to get that honor.

Ronda Rousey is close to a guarantee. She's the biggest mainstream media attraction and was arguably the reason why that historic first main event happened.

Becky Lynch and Charlotte Flair are always in the running for these types of accolades. They're perpetually the top women on the regular roster.

Don't count out Belair to still be holding the Raw Women's Championship, though, or rule out someone like Raquel Rodriguez swooping in with a surprise women's Royal Rumble victory.

Assuming Reigns is still holding both men's world titles, there's even more of a reason to put one of the two women's belts at the forefront, as they are the only other top-tier championships.

It would be a slight to have the United States, intercontinental or tag team titles take this slot instead of the top of the women's division.

Anthony Mango is the owner of the wrestling website Smark Out Moment and the host of the podcast show Smack Talk on YouTube, Spotify and everywhere you find podcasts. You can follow him on Facebook and elsewhere for more.