Never being afraid to sound a sour note, one of my concerns about Chris Johnson ever since his first big preseason performance against the Rams has been whether or not he can run the ball with consistent success. He's a boom-and-bust type runner and, as I wrote the week after that Rams preseason game, when boom-and-bust runners don't go boom enough, they're not very valuable.
Those of you who've purchased Football Outsiders Almanac 2010 (now available on Amazon!) may have noticed a nifty table showing the 10 teams since 1996 with the most Open Field Yards, the average yards per carry by a running back on gains beyond 10 yards. The other 9 teams on that list saw their Open Field Yards decline by at least 0.4 yards per carry and by an average of 0.65 yards per carry. Basically, expect CJ to go boom less often in 2009 than he did in 2010.
If CJ does go boom less often, he needs to have that more consistent success. And, one point in common between 2008 and 2009, was that he didn't have consistent success. Using Success Rate, which measures how often a running back to 40% of the needed yardage on first down, 60% of the needed yardage on second down, and 100% on third and fourth down, Johnson ranked 34th of 49 running backs in 2008 and 32nd of 50 in 2009. During 2008, though, I wrote that his low ranking compared to White (who finished 2008 4th of 49) was misleading because of the distribution of carries, and thought it was a good time to carry that analysis through for the rest of 2008 and also look at 2009.