Brock Lesnar joins Hannah Storm to talk about his start in the WWE and how he adjusted to all the travelling. (1:32)

Every year, when the curtain falls on WrestleMania, WWE chairman Vince McMahon already has a tentative card for the next year's big show in his back pocket.

It's the company's annual tent-pole event and a driver for its entire year's revenue, but moreover, since wrestling is a scripted enterprise, spending the year steering storylines toward WrestleMania is reasonable. Of course, "tentative" is the key word -- or, as ads for wrestling have said for as far back as I can remember: "Card subject to change."

WWE: WrestleMania 32 Where: AT&T Stadium, Arlington, Texas

When: Sunday, 7 p.m. ET

TV: PPV/WWE Network

At its base, it's a weaselly disclaimer, a means of denying liability if, say, "Macho Man" Randy Savage comes down with the flu on the day of the show. In reality, though -- or at least in the pro wrestling iteration of reality -- it's a reflection on the instability of the entire enterprise. It's an in-joke for injuries or wrestlers quitting or storylines gone awry -- the innumerable reasons that expecting a wrestling card booked more than a month in advance to go according to plan is foolhardy.

A year ago at this time, fans were fantasizing about the possibility of The Undertaker vs. Sting or John Cena, Brock Lesnar vs. Daniel Bryan, The Rock and Ronda Rousey vs. Triple H and Stephanie McMahon, and the three former members of The Shield -- Seth Rollins, Roman Reigns and Dean Ambrose -- in a three-way match for the world heavyweight title. But none of those matches will be happening Sunday when WrestleMania 32 invades AT&T Stadium in Arlington, Texas.

Injuries to top superstars like John Cena, left, has forced WWE to bring back the services of Shane McMahon, right, to fill out the marquee for Sunday's WrestleMania 32 card. Kevork Djansezian/Getty Images

Call it the "Lost WrestleMania." Set inside of "Jerry World," with the potential to set the U.S. record for indoor attendance, WWE knew it had to put on the biggest show of the past 15 years, but bad luck, mostly in the form of injuries, have turned the roster into a baby-oiled MASH unit. WWE has tried to paint WrestleMania 32 as a megacard, but it seems as if the talent left off the match lineup could sell more tickets than the one currently on it. But such is the world of pro wrestling, in which the outcomes are predetermined but the physical toll is real. "Card subject to change" isn't just a disclaimer -- it's a way of life.

One year ago at WrestleMania 31, Seth Rollins inserted himself into the main event between Lesnar and Reigns, and stole the WWE world heavyweight championship. He then carried the company for nine months despite being 28 and a relative newbie to the WWE main roster. But in November, he tore his ACL, MCL and medial meniscus performing a routine (and I use that word loosely) sunset flip powerbomb on Kane. As champions are wont to do, he set the yardstick for the rest of the locker room, though in this instance, it was in the most unfortunate way possible.

Randy Orton, the WWE's first unified champion, went out with shoulder surgery in November and was just given a reprieve on neck surgery in January.

Seth Rollins was drafted No. 1 overall by Raw at the WWE draft on July 19. JP Yim/Getty Images

Cesaro, an in-ring dynamo and "smart" fan favorite, went down with a torn rotator cuff in November after wrestling with the injury for two months.

Nikki Bella, fresh off a run as the longest-reigning WWE Divas champion ever, underwent neck surgery last fall.

Neville, who would've been a guarantee as a highlight-reel spot in the seven-man Intercontinental title match, went down with a freak broken ankle two weeks ago in a match on live TV that required his opponent, Chris Jericho, to audible in order to get himself disqualified.

Luke Harper, the disheveled workhorse of the Wyatt Family, went down with a conspicuous knee injury in a dark match after "Monday Night Raw" last week. The Wyatt Family -- once presumed to be Lesnar's opponent at WrestleMania -- isn't even on the card, which may be because Bray Wyatt, the faction's figurehead, suffered a back injury earlier this month. He has since recovered.

Tyson Kidd suffered a severe neck injury in an untelevised bout in June that will keep him out of the ring for at least a year. Kidd tweeted that only five percent of people survive the injury he suffered, and longtime industry journalist Dave Meltzer said on Wrestling Observer Radio that the odds Kidd didn't end up paralyzed were "astronomical."

The biggest absence on the WrestleMania 32 card, though, has to be John Cena. The multi-time champ and industry standard-bearer went under the knife at the hands of (cue ominous music) Dr. James Andrews in January for a shoulder injury. Despite a history of overcoming rehabilitation timelines the way he squashes in-ring foes (and numerous hints that he was attempting a 'Mania comeback), Cena is reportedly out until the summer.

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Then comes the career-threatening department: Daniel Bryan, who won the Intercontinental title at WrestleMania 31, retired in February. Last week, Kurt Angle, an Olympic gold medalist and former WWE wrestler who has been working for other promotions since 2006, weighed in on Bryan's retirement. Angle talked about the difference in protocols during his time with WWE, saying, "When I got my neck surgery, I don't even remember getting cleared to wrestle, I just came back. ... Now, they have to abide by what the doctors tell them. ... I have to commend the WWE because I think they are doing the right thing now."

And then there's Sting, the veteran superstar who was penciled in for the 'Mania card until he injured his own neck during a title match against Rollins in September. He has been shifted to a spot as an inductee in Saturday's WWE Hall of Fame ceremony.

Even the existing members of the active roster have been hobbled in recent months, including Rusev, Paige, Wade Barrett, Sasha Banks, Erick Rowan, Mark Henry and Sami Zayn. Even Reigns, the challenger to world champion Triple H, took a few weeks off in the past month to have nose surgery.

So why all these injuries?

It's impossible to say, though it's not hard to point at WWE's grueling schedule as the root cause. Most wrestlers throw themselves around four or five nights a week, though the untelevised matches tend to be more perfunctory than their high-intensity televised counterparts. (Counterpoint: Rollins blew out his knee at a house show.)

Perhaps we should look to style, since Rollins is among the trendsetters of a new, indie-wrestling-based, hyper-athletic ring style. (Counterpoint: Rollins was hurt on a fairly low-impact move that he had certainly performed hundreds of times before. Additional counterpoint: In the '90s, WWE was replete with acrobatic carwrecks and nuclear pratfalls, so this isn't a new concept.)

WWE's grueling schedule has played a major part in a recent rash of real-life injuries, forcing chairman Vince McMahon to get creative in hopes that WrestleMania 32 lives up to its outsized expectations. Ethan Miller/Getty Images

Perhaps the most hazardous parts of the wrestler's life are the innocuous-seeming ones -- the travel, the exhaustion, the lack of an offseason. It's the plight not of the pro athlete but of the stand-up comic. (Counterpoint: That has always been the case, but all of these injuries are happening now.)

So why now?

Part of the answer is that WWE is more responsive to injuries than they may have been in the past. Part of it is that we, as fans, are much more aware of wrestlers' injuries. It wasn't long ago when a wrestler with a torn rotator cuff would be written off television and we'd be none the wiser, but now we have the Internet rumor mill as our unofficial Injury Report. Some of it, certainly, is the wrestlers' drive to win over fans and grab the proverbial brass ring which, as Vince McMahon urges, is an implicit OK to push the limits if it gets a better response out of the crowd.

But more than anything, it's a freak accident. In another era, they'd probably call it a curse -- you tempt fate by promising to sell out AT&T Stadium, and this is what you get. Of course, Vince McMahon has never had an issue with tempting fate. Thankfully for wrestling fans, WWE isn't wholly dependent on kismet -- or even the health of its wrestlers -- to put on a big show.

The modern wrestling world is overwhelmingly graded by an uneasy ratio of workrate and spectacle, and even though it's almost impossible to pull off a big match without some semblance of physicality, spectacle can take you a long way. WWE will be pushing that ratio to its limits at WrestleMania this year.

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It's worth mentioning that before Cena was rumored to be facing off against The Undertaker at WrestleMania, there were fans imploring for a match between Cena and legend "Stone Cold" Steve Austin, who retired in 2003 due to persistent neck issues and has repeatedly stated he'll never wrestle again. That doesn't stop fans from dreaming about such super-matches -- and why should it? Pro wrestling is a playground for fantasy.

But Cena-Austin isn't happening simply because Cena is laid up. It's not happening because one of the two men has been retired for a decade. It's the same reason we'll probably never see a CM Punk return, or a Daniel Bryan return, or a Kurt Angle return (in WWE), or a Hulk Hogan return. Because even though this is a fantasy landscape, it's real humans wreaking havoc on their bodies to make the fantasy believable. Workrate, such as it is, is masochism in service of spectacle. There might be discernible reasons why so many stars are hurt this year, but what's undeniable is that our expectations have changed. And thanks to the Internet, our fantasies are belted out loudly across the ether.

We'll never see most of our dream matches because they're impossible and because the human body can break under the pressure of fantasy -- but that won't stop us from fantasizing. Even if all the injured stars make full recoveries, this year's WrestleMania is that in a microcosm.

So what do you do when a quarter of your roster is spending WrestleMania on the injured list? You lean on spectacle. The biggest spectacle on the card has to be the Undertaker vs. Shane McMahon bout. Shane is the son of Vince, and is a fan favorite both for his risk-taking inside the ring and his perceived behind-the-scenes virtue. When he returned from a years-long absence from the company several weeks ago, the crowd absolutely went wild.

Despite performing on a part-time schedule in recent years, The Undertaker, top, returns Sunday at the age of 51 to face 46-year-old Shane McMahon in a Hell in a Cell match. JP Yim/Getty Images

Shane appears to be in the best shape of his life, but he's also 46 and was never a full-time grappler. His opponent, The Undertaker, is 51 and has been wrestling only sporadically for the past five years. They're facing off inside Hell In a Cell, a cage match known for its high spots and brutality.

Two years ago at WrestleMania, The Undertaker went straight from the ring to the ER, and one can only hope that such a fate won't befall either of the men in this match. Shane, for his part, has engaged in more shocking high-wire dives than just about anybody in recent memory. The storyline here is that Shane has come back to wrest control of the company from his father, and Vince has called in The Undertaker as his enforcer. It's an oddly (or unintentionally) self-aware angle. Vince's argument seems to be mainly that he's in control of the writers' room, making Taker's assistance less a deus ex machina than a fait accompli.

The subtext, though, is these two men who owe their careers to WWE are putting their lives on the line to make sure WrestleMania lives up to its outsized expectations. With the history between The Undertaker and Shane McMahon -- and the gaping hole in the roster they're going to try to make up for -- it's safe to assume they'll try something amazing and accept the injuries that come with it. It's just part of the business.

It may not be the WrestleMania that fans were hoping for, but there's a vibe of urgency bubbling underneath the surface, and despite the inherent silliness in the McMahon familial drama, there's a powerful reality in that urgency. There may be no Rock, no Sting, and no John Cena, but this is all part of the game. "Card subject to change" and all that.