Watching for wear and tear

Last week, Brad Childress spoke of the "fierce urgency of now." He could quote great running backs like LaDainian Tomlinson or Earl Campbell on the urgency of winning soon.

Just 27 games into his NFL career, Adrian Peterson already has become Jim Brown's favorite runner, Bears coach Lovie Smith's pick for best player in the league, and the best back ever to wear purple.

If young quarterbacks are like time-delayed fuses, great young backs, especially those who refuse to avoid contact, are fireworks. They flash, then fade.

In the modern NFL, the success of the fleet is often fleeting. Tomlinson, formerly the NFL's best back, looks this season like he's running under water. He carried the ball more often than any other back in 2006-07, and now he cuts like a butter knife through gristle.

Edgerrin James, signed as a savior in Arizona, carried the ball more than any back from 2004 to 2007. Now that he moves like Fred Sanford, he's lost his starting job.

Entering this season, James, Tomlinson, Rudi Johnson, Shaun Alexander and Willis McGahee had carried the ball more than any other backs from 2004 to 2007. Last week, Washington cut Alexander, a former MVP.

Would you sign any of them to a long-term contract? Not unless universal health care becomes a reality.

Emmitt Smith could curl up like an armadillo when a defender loomed, and Smith's pain tolerance allowed him to excel even when playing with a separated shoulder.

For all the NFL Films-inspired nostalgia about the good ol' days of pro football, when toothless linebackers threatened to gouge eyes, today's players are bigger, faster, stronger and more violent. Today's running back is as endangered as a wood owl near a logging camp.

Peterson's greatness is not based on elusiveness. He'll make a defender miss with his speed and cuts in the open field, but most of his carries end with him ramming a defender and twisting awkwardly for the extra yard. What makes him an admirable competitor makes him an injury risk.

The only minuses attached to Peterson coming out of Oklahoma were his upright running style and his injury history, which are linked surely as subprime mortgages and foreclosures.

Peterson doesn't go down easy. He doesn't seek the sideline. He doesn't settle for the routine 2-yard push into the pile. He doesn't quit when a half-dozen tacklers pile on.

Childress uses the eminently capable Chester Taylor to rest Peterson, yet he ranks third in the NFL in carries this season.

Who could blame Childress for putting the rest of the season in Peterson's hands? Childress' job is on the line, and Peterson is the Vikings' best player and best bet to break a big play.

When it comes to Peterson's career, the Vikings must acknowledge the fierce urgency of now.

Tonight, Peterson will face the Bears, who must look to him the way the carpool lane looks to a rush hour commuter. In a must-win game for the home team on national TV on a Sunday night, you can expect Peterson to rush for his usual 100, if not 200. You can expect fast-as-a-flashbulb bursts and oblique open-field cuts. You can also expect him to take all of those extra hits that shorten careers.

If you're a Vikings fan, you should enjoy him while you can. Peterson is built to thrill, not to last.