In his just-released autobiography, "The Bus: My Life In and Out of a Helmet," future Hall of Famer Jerome Bettis describes the harsh physical realities of the NFL, and what it took to survive 13 seasons and eventually become the league's fifth all-time leading rusher and a Super Bowl champion.

During the Pittsburgh Steelers' 2000 season, Bettis rushed for 1,341 yards -- and did it despite playing with turf toe, a lump the size of a cue ball in his lower left leg, injured ribs and a bad left knee.

On game week I would only practice on Thursday and Friday, sometimes only on Friday.

Saturdays weren't any fun, though. Even with the limited practice schedule, my knee would swell. So every Saturday a team doctor would come in and drain the knee. The needle was as long and thick as a No. 2 pencil. Think about that for a minute. Then the doctor would extract all sorts of pus, blood, and little pieces of cartilage.

Yeah, it hurt. Damn right it did. But if I wanted to play, that's what I had to do. Pain is part of the game. It's as much a part of the game as the crowds or the Miller Lite commercials or the TV cameras. If you can't endure pain, you can't play in the NFL.

I let USA Today's Jarrett Bell, whom I've known for a long time, use me as a centerpiece for a story he was doing on the toll an NFL season takes on your body. He saw it all. My purple ankle. My bruised butt. The red welts on my back. The scars. The scratches and gashes on my arms and legs. The torn tendons in my thumbs. The ring finger that is missing a chunk of flesh.

He saw me try to get out of bed that morning. It took forever. I told him that sometimes I couldn't walk down the stairs in my house. Instead, I had to sit on the top step and very, very slowly slide my way down on my butt.

This was the life I had chosen, so I wasn't about to complain. But I don't think the average NFL fan has any idea what it takes to play the game when you're injured. Broken ribs are one of the worst injuries. I know, because one time I broke three ribs, which is a pretty rare thing. Usually you just break one, but I had the trifecta.

You can get an X-ray to detect the breaks. But an X-ray is useless when it comes time for the doctor to inject you with the painkillers necessary to play in a game. It's not like he can look at the X-ray and connect the dots. It doesn't work that way.

No, you have to raise your arm and then he sticks a needle in there, taps on the bone with the needle point to find the exact spot of the fracture, injects the painkiller, and then removes the needle. Then he gets a new needle, inserts the needle, taps on the next rib bone, injects, and then removes. And then he gets another needle, inserts, taps, injects, removes.

And did I mention that you can't move while he's doing this? If you move, and the needle jabs too deep, he could puncture your lung.

Those painkilling shots were a necessary evil. With broken ribs, the chances of them breaking off and puncturing something were very small, so it was an acceptable risk for me. The possibility of me injuring them more was tiny.

But I would never take a painkiller in my knee or hamstrings. Those are parts of the body where you need to feel the pain. If you can't, then a sprained ligament might turn into a torn ligament.

My teammates and coaches never pressured me to take painkilling shots. But there is an unspoken understanding about playing with injuries in the NFL.

A coach and the other players need to know they can count on you. If a guy doesn't take a painkiller, he's labeled as soft. They don't know if they can truly depend on you.

Me and pain had a great relationship. We always found a way to work it out. An injury might hurt like hell, but my threshold for pain was pretty high.

The next season, in a Dec. 2 game against the Minnesota Vikings, Bettis suffered a severe groin injury. But that isn't the real reason he missed the Steelers' AFC divisional playoff game against the Baltimore Ravens.

I didn't know it at the time, but I had torn 30 percent of my groin muscle from the bone. At first, the pain was intense. But once it settled down I thought I could go back in. I tried, but the longer I played the more it hurt. Something was seriously wrong.

This was a rough one because time and rest were the only things that could heal that type of injury. But I didn't have the luxury of time. The playoffs started in January and no way was I going to miss the postseason.