Le'Veon Bell's 2,215 offensive yards last season leave little doubt about where he belongs in the NFL rushing pantheon.

Bell is a top-three back, with or without Adrian Peterson. His versatility places him there.

But former Pittsburgh Steelers great Jerome Bettis is thinking bigger for Bell, which requires a step back to assess Bell's longevity.

Here are Bettis' comments, as told to the Post-Gazette's Ed Bouchette and broken down into two parts.

1) "I think if he continues on his course, I think he can be one of the best that ever put on a uniform — not just a Steelers uniform, one of the best running backs ever."

2) "I think he’s special. He’s a special player on the field, everything you see him do. He has the frame of a big back but the agility of a smaller running back, which makes him a very, very special player.

"He’s a big back but also able to catch the ball out of the backfield, be elusive, do so many things. Being a three-down running back, that, in and of itself, is a special treat to have."

Bettis makes several agreeable points, especially as it pertains to Bell's combination of size (6-foot-1, 230 pounds), elusiveness and pass-catching ability. Bettis doesn't mention Bell's patience as a runner, which might be his best attribute.

As it stands, Bell's second season of 1,361 rushing yards and 854 receiving yards (on 83 catches) is enough to believe Bell's 10-year arc will be fruitful. Bouchette rightly points out that Bettis, Franco Harris, John Henry Johnson and Bill Dudley -- all Hall of Famers -- never produced a season like Bell just did.

For Bell, ability isn't the roadblock to greatness. Staying on the field would be.

Bell will have played in 29 of 36 career games including playoffs if he serves his three-game suspension for marijuana. That's about an 80-percent clip, which isn't bad, but to reach the all-time lists, playing 90 percent of the action is more helpful.

Consider that Bettis himself played in 16 games during seven of his first eight seasons. In the other year, he played 15.

That's not to say Bell will be injury prone or will run into more trouble. But he has to prove he can do it. Playing in Bell's favor -- his running style is conducive to a long career. He can rely on vision and smart elusiveness rather than aggressive cuts that can grind down a player's knees. Bell had 4.6 speed out of Michigan State, but can get the yards he needs without burning.

Another couple 2,000-plus-yard all-purpose seasons and this argument is shut down for good. First, Bell needs to prove he'll be on the field to do it.