WWE Royal Rumble 2016 surprise entrants: Could Triple H, The Rock or The Undertaker feature?

This year's first major WWE card — Royal Rumble — is set to take place this Sunday and this time, the WWE Heavyweight Championship is on the line in the big match!

For the first time in WWE history, the reigning WWE World Heavyweight Champion must defend his title in the 30-superstar Royal mumble Match when champion Roman Reigns enters the annual melee on 24 January. Check out the match card for the upcoming event below:

• Kickoff Match – Fatal Fourway Tag Team Match: The Dudley Boyz vs The Ascension vs Jack Swagger and Mark Henry vs Darren Young and Damien Sandow. (Note: The winners of the match will get spots in the Royal Rumble)
• Tag Team Championship Match: The New Day (c) vs The Usos
• Last Man Standing Match for the Intercontinental Championship: Dean Ambrose (c) vs Kevin Owens
• United States Championship Match: Alberto Del Rio (c) vs Kalisto
• Divas Championship Match: Charlotte (c) vs Becky Lynch
• Royal Rumble Match for the WWE World Heavyweight Championship

Surprise entrants are one of the most exciting things about Royal Rumble each year and fans cannot wait to see who they are in 2016. WWE has dropped a few hints regarding who might appear in this year's Royal Rumble.

On Monday Night Raw, announcer Byron Saxton said Reigns "could find himself facing six Royal Rumble winners". Now, Brock Lesnar, Alberto Del Rio and Sheamus have been confirmed for the match but who could the other three be? Here are the potential candidates:

Triple H

The WWE COO won the Royal Rumble in 2002, and he's almost certain to enter the match. He hasn't appeared on Raw since he was attacked by Reigns at TLC 2015, but he's the favourite to win the WWE World Heavyweight Championship on Sunday, setting up a potential main event clash with Reigns in the main event of WrestleMania 32.

The Undertaker

The Deadman, who won Royal Rumble in 2007, hasn't competed in the match since 2009 but he has been extremely active in 2015 compared to the last few years. The Undertaker has been part of the Battleground, SummerSlam, Hell in a Cell and Survivor Series PPVs. Without a clear opponent for WrestleMania 32, the Royal Rumble could help set up The Undertaker's next big match.

The Rock

It's unknown if The Rock will wrestle at WrestleMania 32 but the former WWE star and Royal Rumble 2000 winner has confirmed his participation at the big event, which will take place in April, and an appearance on Sunday could help set up a match on WrestleMania 32.

Royal Rumble 2016 airs live Sunday 24 January at 8 ET/5 PT on the WWE Network.