WrestleMania 29 is barely over, but that hasn’t stopped fans from speculating about who might fight at WrestleMania 30.

The 2013 event was called the biggest in WWE history, taking place at MetLife Stadium in East Rutherford, N.J., and in front of a record-setting crowd. The 2014 event, though, could surpass this year’s, with rumors of big stars set to take part in the event in New Orleans.

There are more than 300 days left until WrestleMania 30 and a lot can change in the WWE. With that said, below are four potential matchups that could be in one of the main events next year.

CM Punk Vs. Stone Cold Steve Austin

This potential match has been discussed for the past few years.

On multiple occasions, Punk has said that a WrestleMania bout with Austin would be his dream matchup. The two have teased a future match with confrontations on both on “Monday Night Raw” and in a 2012 interview with Jim Ross.

Punk is often viewed as this generation’s version of Stone Cold. His now infamous promo from June 2011 made him a beloved “bad guy,” much like Austin’s King of the Ring promo in 1996 did for him.

Austin hasn’t been in the ring since he lost to The Rock at WrestleMania 19. Injuries forced him to retire early, and the former superstar doesn’t have much incentive to wrestle again. He’s busy with a reality TV show and his own podcast, and may feel that coming back for one more match may not be worth the risk.

A match with Punk, though, would be one of the biggest in WWE history. It would generate millions of dollars and likely headline the biggest WrestleMania of all time.

In his WrestleMania 29 match with the 48-year-old Undertaker, Punk showed that he can help put on a great show with a wrestler who’s been limited by injuries. Both Punk and Paul Heyman have said they’ve suggested the idea to Austin. It’s up to the biggest star in WWE history to make it happen.

John Cena Vs. The Undertaker

There were many questions regarding the Undertaker’s health as he entered his match with CM Punk. The two ended up stealing the show, indicating that the “Dead Man” has at least one more good match left in him.

After defeating the likes of Punk, Triple H, Shawn Michaels, Randy Orton and Kane in recent years, there are only a few worthy opponents that have yet to challenge the Undertaker’s undefeated WrestleMania streak.

At 21-0, it’s hard to believe that the Undertaker would lose to anybody at WrestleMania 30. John Cena, though, might have the best chance of ending the streak.

Cena has been the face of the WWE for the past decade. His win-loss record is better than almost any wrestler’s in recent history, and he rarely loses a match without some type of interference. If Cena was to face the Undertaker, it would put a lot of doubt in the fans’ minds as to who would leave the ring victorious.

As he approaches age 50, the Undertaker’s days of wrestling are probably nearing an end. If WrestleMania 30 ends up being his final match, there’s at least a chance that he’ll lose on the grandest stage of them all. The Undertaker’s streak has become almost bigger than WrestleMania itself and a superstar of Cena’s stature would be one of the few wrestler’s that would be given the honor of ending it.

The Rock Vs. Brock Lesnar

Of all the part-time wrestlers that came back for WrestleMania 29, The Rock and Brock Lesnar may be the biggest draws. Through The Rock’s movie career and Lesnar’s stretch as the UFC heavyweight champion, they are the biggest pop culture icons in the WWE.

The two have a history against each other in the WWE. Lesnar defeated The Rock at SummerSlam 2002 to become the youngest WWE champion in history.

If you believe the rumors, the two were supposed to have a confrontation on the past edition of “Raw,” setting up a potential match down the road. The Rock’s failure to show up because of an injury forced WWE creative to scrap those plans.

If The Rock and Lesnar are set to fight at a Pay-Per-View, WrestleMania 30 is likely the only place for it. Vince McMahon wouldn’t allow these two megastars to face off on anything but the biggest event of the year.

Triple H Vs. A Member of The Shield

Even though he’s transitioned from full-time wrestler to COO, it’d be a surprise if Triple H didn't lace up his boots for WrestleMania 30. He continues to come back for the biggest WWE events, and Lesnar’s failure to force him into retirement is an indication that he isn’t close to being done.

If the usual part-timers like The Rock, the Undertaker and Lesnar are in other matches, Triple H may have to find someone on the full-time roster to fight. A lot can happen over the next year, but one of the members of The Shield may be the most likely candidate.

Ever since making their debut at Survivor Series, Dean Ambrose, Seth Rollins and Roman Reigns have become a force to be reckoned with in the WWE. They have yet to lose a match, defeating superstars like Cena, Sheamus, Ryback, Big Show and Chris Jericho.  

It makes sense for Triple H to take on a member of The Shield on multiple levels. For storyline purposes, the COO would try to stop one of the wrestlers that has been wreaking havoc on “Raw" and various PPV’s. Also, putting one of the WWE’s rising stars in a match with Triple H would help elevate them to a new level.

It remains to be seen whether Ambrose, Rollins or Reigns will emerge as the best from the group. Whoever has the quickest rise to the top could be in one of the biggest matches at WrestleMania in 2014.