As we approach SummerSlam, it's important to remember anything can happen in WWE at any given time.

Lately, it seems even the writers don't know what will happen until midway through the shows, with scripts appearing to be scrapped and rewritten on the fly.

This can be both confusing and fun for fans, since you can never be sure what shocking twists are around the next corner.

The card for The Biggest Party of the Summer on Sunday may also be deceptive. A number of Superstars are not scheduled to make an appearance, but we've already seen Goldberg replace The Miz in a match with Dolph Ziggler, while Roman Reigns' plans to name a SummerSlam opponent have gone out of the window.

So let's attempt to get ahead of the game and figure out which Superstars could be making a surprise appearance at this year's pay-per-view in Toronto.

Sasha Banks

Ever since Sasha Banks disappeared from WWE programming after WrestleMania 35 in April, there have been endless theories over her potential return.

None of them have been confirmed, so we're left tossing out more possible suggestions about when we'll see The Boss in a WWE ring again—and SummerSlam is as good a guess as any to mention.

Nothing has been hinted at in storylines, which makes it hard to pinpoint what her involvement would be.

She could have shown up at Extreme Rules in July to help Bayley fight off Alexa Bliss and Nikki Cross, or been utilized as the next challenger for the Raw or SmackDown women's titles if Natalya and Ember Moon weren't already in those positions.

Maybe Moon will get attacked and Banks will take her place to pop the live crowd, though that would be harsh on The War Goddess who deserves her own time to shine. Perhaps Banks will attack Bayley to set up a feud between the two for Clash of Champions in September.

If The Boss' leave of absence is to end, WWE might be inclined to choose SummerSlam for her return to ensure a large audience witnesses it.

Shawn Michaels

It will be no surprise if The Miz is ringside for Dolph Ziggler's match against Goldberg, but it's harder to find a reason for Shawn Michaels to be there.

The booking behind this match has been odd, as this feud is a random one that has revolved around The Showoff having simultaneous problems with Miz, Michaels and besmirching Goldberg's name, unprovoked.

WWE teased the idea HBK would be the shock opponent for Ziggler on Monday's Raw but immediately diverted to Goldberg. Is that really going to be the end of Michaels' part in this, though?

Raw ended with a superkick out of nowhere, so maybe The Heartbreak Kid will show up to lay out The Showoff after he gets wrecked by Goldberg.

That might be saved for the next edition of the red brand, when The Miz is supposed to get his hands on Ziggler. But if that's the direction WWE is taking, it would make HBK's appearance at SummerSlam even more of a surprise.

Buddy Murphy, Samoa Joe and Others in Roman Reigns Attack Storyline

The storyline around the two attacks on Roman Reigns has pointed toward Rowan and Daniel Bryan being the culprits after Buddy Murphy named Big Red as the driver of the forklift that tipped stage equipment over The Big Dog.

A confrontation is now inevitable, but this could be booked as a much shorter segment if it's just a backstage brawl of some kind.

If that happens, all sorts of Superstars could be involved, including Murphy and Samoa Joe, who have both been involved in the story.

Perhaps Joe's support for Reigns after his car was hit by another on Tuesday's SmackDown will manifest itself again, with The Samoan Submission Machine helping The Big Dog against Bryan and Rowan.

Maybe this is all a ruse and Murphy was mistaken and some other Superstar will be revealed as the real attacker at SummerSlam.

There are a lot of ways for WWE to involve several wrestlers here, so it's impossible to guess all those who could show up to shock the fans.

Lita

It might be a stretch for Sunday's SummerSlam, but whenever Trish Stratus is brought back into the WWE fold, Lita isn't far behind.

Their friendship is built into the WWE Universe consciousness now, and Lita even teamed with Stratus at Evolution and the next night's episode of Raw in October.

It's doubtful she will get involved in Stratus' match against Charlotte Flair on Sunday, but she may be ringside to witness what may be her friend's farewell bout.

The Hart Family

With SummerSlam taking place in Canada and Natalya wrestling for the Raw Women's Championship, the temptation to have members of The Hart Family make some sort of appearance is so high that it will be more shocking if it doesn't happen.

Bret Hart is scheduled to be at the SummerSlam Meet and Greet beforehand, so he'll be in the area and could easily be ringside or backstage for any plans WWE has.

It was specifically mentioned numerous times how the Sharpshooter is a family legacy, with Bret being the one who really put the move on the map. If anyone could be shown coaching Natalya backstage, it's him.

Other members of the family could be in attendance, though, even if they have little to do at SummerSlam. The Harts are royalty in Canada and the Toronto crowd would love to see them.

Shane McMahon's Backup Crew and Their Adversaries

During "The Kevin Owens Show" on SmackDown Live this week, Elias came to the aid of Shane McMahon and double-teamed KO, so it's likely he will do the same at SummerSlam to thwart The Prizefighter.

Shane-O-Mac has surrounded himself with people to do his bidding in recent weeks, with Elias being joined by The Revival, The B-Team and Drew McIntyre in his corner.

They aren't advertised as part of the card, but they could show up to cheat the system and put the odds in McMahon's favor.

However, they may be met with some force in retaliation. McIntyre has been feuding with Cedric Alexander lately, and there had to be some reason for WWE to show a backstage segment featuring Elias picking on Chad Gable.

What should be a one-on-one match between McMahon and Owens could turn into a three-on-three brawl.

Ronda Rousey

Ronda Rousey has been absent from WWE television since losing the Raw Women's Championship to Becky Lynch at WrestleMania on April 7.

The former UFC star is such a major name that it would be strange for WWE not to advertise a potential return at SummerSlam, but the company's target for improved ratings might be the following night's Raw.

WWE needs to raise viewing figures for both brands, so if Rousey attacked The Man and declared herself the next challenger for the Raw women's title, it would be a storyline the WWE Universe would want to follow.

Natalya and Rowdy also have a close friendship, which might mean further motivation for The Baddest Woman on the Planet to go after Lynch if she makes The Queen of Harts tap out on Sunday.

The idea of Lynch vs. Rousey in a rematch would be a great marquee event for the Clash of Champions on Sept. 15, and there's no better time to get the ball rolling on that than at SummerSlam.

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