There is no doubt in the world that wrestling, at any level, isn't for the weak. It isn't for the type of people who will sit out a match due to pain. I mean, many wrestlers will only miss face-offs if there is literally no chance they can make it, and honestly, they would have a doctor roll them in a hospital bed if that was an option.

What makes it even harder to believe? How long an average wrestler's career will last. Looking at the long, long list of injuries these gladiators endure, it's difficult to grasp the fact that they can last over five years, let alone step in the ring in their 40s and 50s (and in some cases even older).

From torn quads, to torn ACL's, to chronic knee/hip/back problems, all the way to broken necks. In this sport, we've seen it all; over and over.

Some of these injuries would be enough to keep the average human being out of work for months. But for these rare breeds, they are simply nicks and bruises.

Sadly, several of competitors were unable to see their maximum potential due to their history of injuries. Others have fought through every obstacle in order to remain in the spotlight. It really comes down to which guys can tolerate pain the best (die-hard wrestling fans know exactly which guys I am talking about).

Its a dog-eat-dog world out on the mat. These are some of strongest, most vicious men in all of sports, not mention there are props involved.

Regardless, the list of wrestlers you are about to click through can't seem to stay healthy. Ever.

Here are the Top 15 Wrestlers Who Are Made Of Glass:

15 15. Johnny Gargano

via eyeonwrestling.com
via eyeonwrestling.com

Johnny Gargano has been injured a decent amount. One of which was truly significant.

The craziest part about it? He fought through it.

He was mainly suffering pain in his back, but stated that he was losing feeling in his legs and arms. Gargano feared that he may have even been paralyzed. He fought through the pain and completed the match. That was in 2012.

Gargano also had a rough hairline fracture in back in 2008. He is a true warrior, but staying healthy isn't always in the cards for him

14 14. Chris Sabin

via wrestlingnewsworld.com
via wrestlingnewsworld.com

Chris Sabin has had plenty of injuries over his impressive 13 year career, but none worse than his most recent.

He suffered an injury to his neck, which is, well, not good. Many believe it could be career threatening, but Sabin is hoping that isn't the case.

The veteran signed on with Ring of Honor and is looking overcome yet another setback as he battles through his bumps.

13 13. Mark Henry

via bleacherreport.com
via bleacherreport.com

Mark Henry put his super strong body to the test, as he was far more than just a wrestler. Henry was also a powerlifter, Olympic weightlifter, and a strongman.

His most significant wrestling injuries came in 2006 when he suffered a torn patella tendon, and in 2014, when he suffered a dislocated elbow mixing it up with Brock Lesnar.

Henry hasn't let the injuries stop him, as his wrestling and lifting career are still carrying on.

12 12. Mark Briscoe

via therealtsm.com
via therealtsm.com

A lesser known wrestler from the Ring of Honor, Mark Briscoe has had himself some serious knee issues as the grind of the independent circuit is grueling as well and with less of the medical care.

Briscoe even had some bad luck outside of the ring, getting in a motorcycle accident in 2007 that dislocated his foot. The injury somehow caused him to miss no action. These guys can't be human.

11 11. Daniel Bryan

via pwmania.com
via pwmania.com

Daniel Bryan's biggest concerns can be compared to those of professional football players as his neck has taken a beaten over the years.

Bryan, while a tough competitor has been sidelined for quit some time with his neck and concussion problems. His most concussion recent was suffered in June of 2015, and it might leave the door closing on a bright star. Concussions are very scary to play with.

10 10. Sami Zayn

via 411mania.com
via 411mania.com

Sami Zayn entered a match against John Cena this past spring and suffered a shoulder injury in the process but toughed it out and completed the match in front of his hometown crowd in Montreal.

It wasn't the first time that Zayn had experienced shoulder problems. In fact, it is has been a recurring theme throughout his career. He was forced to undergo surgery once again but is expected to return soon.

9 9. Ryback

via cagesideseats.com
via cagesideseats.com

Ryback has struggled and has been beaten down over the years, but nothing compares to that disgusting, disturbing and downright horrifying staff infection in his knee in July of 2015.

Just google Ryback injury, and you will get an idea of just how insane it was. Of course, Ryback has endured other injuries prior to this infection including an ankle injury that could have been career-threatening.

8 8. Evan Bourne

via thfire.com
via thfire.com

Evan Bourne had a bright career ahead of him as one of WWE's most talented wrestlers/entertainers.

That was until he suffered an unbelievably disturbing and painful foot injury back in 2012. The injury was severe enough to keep Bourne away from action for quite some time. Eventually, Bourne would leave WWE.

Bourne would then return to the independent circuit and is now wrestling in Japan. Oh, what could have been.

7 7. Dolph Ziggler

via dailywrestlingnews.com
via dailywrestlingnews.com

The past couple year's have not been particularly kind to Dolph Ziggler.

In 2014 he went down with a concussion that seemingly altered his career. Ziggler was once World Champion but has since been stuck performing at the mid-card where he will likely spend the remainder of his WWE career.

It's a real shame considering how talented Dolph Ziggler is in the ring but unfortunately the company has lost faith in Ziggler.

6 6. Kurt Angle

via youtube.com
via youtube.com

As often as Kurt Angle was injured, he was not one to miss many matches.

In fact, Angle did one of the most crazy things that anyone could ever imagine. I mean, you have to be verifiable insane to do what Angle did. I can't even believe I'm about to type it.

Okay, here goes: Kurt Angle competed with a broken neck. As crazy as it sounds, his doctor actually told him that he couldn't hurt it anymore, so he went out and competed. Wow.

5 5. John Cena

via bleacherreport.com
via bleacherreport.com

Some may be wondering, why is John Cena on this list? He rarely misses matches?

Well, actually, he is. We just never hear about it because nothing can keep the beast from stepping into the ring and throwing down.

He has suffered injuries to his hip, elbow, blood cuts, neck and had a torn pectoral tendon, but you wouldn't know it watching him. It's hard to believe he is a human being. I mean, he can't be, right?

4 4. Mr. Kennedy

via bleacherreport.com
via bleacherreport.com

Mr. Kennedy was on track to be one of the most popular and best wrestlers in WWE for a moment.

His self-introductions and eccentric personality made him an easy fan favorite, but a series of injuries put a halt to what was an extremely promising career. A shoulder injury suffered against Randy Orton was the straw the broke the camels back as Kennedy was never the same and soon left WWE.

Care to see what he is up to? Tune in to TNA.

3 3. Randy Orton

via pinterest.com
via pinterest.com

Randy Orton has a long history of shoulder injuries, with his most recent coming in the fall of 2015.

The 12-time world champion has overcome a number of these type of injuries, so generally it would be no surprise to see him back quickly, but this one is significant. He is in danger of missing WrestleMania 32. It would be the first one without him since WrestleMania 19.

Orton remains a staple on WWE programming and will hopefully return to action sooner than later.

2 2. Rey Mysterio

via bleacherreport.com
via bleacherreport.com

Rey Mysterio was once one of, if not the most popular wrestler in all of WWE. His high flying acrobatic style had fans going wild every time he stepped into the square-circle.

That out of control approach has caused Mysterio to compile a long, long list of knee injuries, with the most recent coming during smackdown in 2014. He was quoted by WWE.com in 2011 as saying, "the inner part of my knee had no more cartilage. So, the inner part of my left knee is bone on bone, arthritic.”

That isn't too surprising given the fact that he has had multiple ACL surgeries. It's unlikely Mysterio has a whole lot left in the tank.

1 1. The Undertaker

via pinterest.com
via pinterest.com

The list of the injuries the famous Undertaker has suffered goes on, and on, and on, and...on.

From his hip and back, to his shoulder, groin and bicep. The Undertaker has sure felt the pain over the years. He hit a breaking point when he suffered a severe concussion in a match with Brock Lesnar in 2014.

It seemed as if they might be the end of The Undertaker in WWE, but that wasn't the case. Much to the fans delight, he made his return to the ring in 2015.