Rams running back Steven Jackson, whose 1,528-yard season in 2006 was undermined by an injury-shortened 2007, is entering the final year of his rookie contract in 2008.

And he’s hoping to get paid big money to continue his NFL career thereafter.

“I think I’ve been a good person on and off the field,” Jackson said, “so I expect to be rewarded.”

But as the Seahawks (with Shaun Alexander), the Cardinals (with Edgerrin James), and the Chiefs (with Larry Johnson) have learned, tailbacks shouldn’t be paid based on past performance.  If the NFL is a “what have you done for me lately?” league, running backs should be regarded as its “what will you do for me today, and tomorrow?” commodities.

The cumulative bumps and grinds and bruises and sprains add up quickly for the guys who carry the pig into a mass of human beings who could swallow a whole hog.  And the mere fact that a guy has achieved long-term financial security might make him less inclined to continue to thrust himself into the fray with the same reckless abandon he displayed before he got paid.

So the Rams will need to ask themselves not whether Jackson should be rewarded for his past actions, but whether he’s likely to continue to do in the future that which he has done in the past.

In making that assessment, they’ll need to put his performance in 2008 into proper perspective.   “Well, we all know what happens in a contract year:  you ball out,” Jackson said, laughing.  “So, I expect to.”

But what will happen in 2009, 2010, and/or 2011?  That’s what the Rams need to figure out before they write a huge check to Jackson.