This is some great insight into what some of the guys go through when they get hurt.

Eight months after his NFL career came to an end, former
Seattle Seahawks WR Ricardo Lockette discusses the hit that almost killed him.

It was like being in a car accident. Everything was fast, then it was suddenly slow motion. I was running down on punt coverage against Dallas last season, like I’ve done a thousands times before. I pushed off on my blocker. I turned to my left. I saw a white jersey.

Car crash.

I hit the ground, and I heard the sound you never want to hear. When you have a brush with death, people always say you see a light. Well, I didn’t see a light. I heard a noise. You know the noise I’m talking about — like when you were a little kid, bored at a family party, and you ran your finger around the top of your auntie’s wine glass. It’s that weird, far-off ringing sound.

The rest of the story:
http://www.theplayerstribune.com/am-i-about-to-die/