Fans were left holding their breath at the end of RAW Monday night -- not due to the sight in the ring, Roman Reigns standing tall -- but the scene outside the ring, with medical personnel looking at Seth Rollins.

Toward the end of the match, Rollins tried a springboard attack against Reigns, who sidestepped the move. As he landed in the ring Rollins immediately bent over, grabbing towards his right knee. Reigns then clotheslined him over the top rope, and when Rollins hit the ground he again grabbed at his knee.

Medical staff immediately made their way over, and while the rest of the match went on for the next couple minutes in the ring, Rollins was helped to the back off-camera. While we see wrestlers fake injuries often, this one seemed real for three big reasons that those “in the know” have come to look for when it comes to injuries.

The first is simply how it happened. At first glance, it appeared that Rollins grabbed his knee for the first time when clotheslined by Reigns. If that was the case, it wouldn't have been a ridiculous stretch to think that it was a work to write him out of the end of the match.

However, for him to grab the knee on two separate moves makes it seem more real. If he was trying to simply sell a fake injury, he would've simply done it after the clothesline. There was no reason to grab the knee after the springboard move. Also, why sell an injury when taking a finisher (say, a Superman punch from Reigns) would've sufficed in that situation?

The second thing is the dreaded “X” sign from the referee. For those who aren't aware, when an actual injury happens in the ring that requires immediate attention, the referee will almost always make an X with his arms to signal this to the staff at ringside and in the back.

For years, you would have only seen this during a real injury, and fans could tell that way. However, in recent years, as fans have caught on to this sign, there have been times when they've used this as part of the in-ring action to sell an injury, and make the situation seem more real. In this case, Charles Robinson did put the X sign up and made sure the ringside doctor ran over to the ramp to check on Rollins.

The third is a small thing in the big picture, but it could be another sign that it was a real injury. Wrestlers in America will almost always sell an injury on the left side of their body. It's how they're taught, and with rare exceptions, that's what you would see in the WWE.

The reason for this is simple: If you're favoring a body part, you want that to be easily exploited by your opponent when telling that story. So as most wrestlers are right handed, you want your left side to be vulnerable.

This actually isn't the case everywhere, as Mexico trains to sell on the right side. That was one of the reasons Mistico had such a hard time translating to the WWE. In this case, Rollins grabbed his right knee. Most wrestlers would have instinctively sold on their left side.

None of these things are conclusive. And it's certainly possible that these could have been engineered to make the injury seem more real. However, there is a lot of smoke there to make this seem like a real injury.

If serious, it couldn't come at a worse time for Rollins, who has looked so good in recent months, and for WWE, which is suffering from a bit of an injury rash already. Only time will tell, but those who caught some of those early signs are certainly holding their breath til they get the all-clear.

The Rest of RAW:

-As mentioned at the top, Roman Reigns ended up standing tall at the end of RAW. This followed a 3 on 2 handicap match where Reigns and John Cena teamed against Rollins, Randy Orton and Kane. This was supposed to be a six-man tag, however Dean Ambrose was taken out in an especially brutal beatdown early in the night.

The match broke down at the end, after a DQ finish, and featured both sets of teammates accidentally hitting each other, as Kane punched Orton, Orton responded with an RKO on Kane, and Reigns ended up accidentally spearing John Cena.

This build toward Battleground hasn't been the best, but if nothing else it's made Roman Reigns look like a million bucks.

- Before that match, Ric Flair came out and put over John Cena, and to a lesser extent Roman Reigns. An interesting thing happened as Flair exited the ring. He first shook Reigns' hand, as he came out first, and then when Cena came out, Cena stopped Flair on the top of the ramp. He handed Flair the World Heavyweight Championship belt, and told him to hang on to it.

While it might be a meaningless gesture from Cena, who truly respects Flair, some are speculating that it could be the end of the WWE World Heavyweight Champion carrying both belts.

- The most buzz from RAW came from a WWE 2K15 commercial that featured Sting. An orchestra played the “Crow” theme, while you saw his silhouette descending and then walking with a bat. It showed his face at the end.

Quite frankly, it was just a really cool commercial, and while it doesn't mean Sting is going to be on TV in any capacity in the immediate future, it was great and somewhat surreal to see that image on WWE television. You can see the commercial here.