Does CJ’s low success rate in 2009 mean bad things for 2010?

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.

First, I thought I’d run the full numbers for 2008 for Johnson and White based on down and distance.  I’ve split down and distance into 8 different categories: first down on 10 or more and <9 (generally -and-goal) and each of second and third/fourth downs on 7+, 4-6, and <4.  I’ve also added in the number of carries, so you can see what kind of split Fisher et al. chose.

1&10+ 1&<10 2&7+ 2&4-6 2&<4 3&7+ 3&4-6 3&<4
Johnson 49% (132) 56% (9) 20% (49) 56% (16) 70% (23) 20% (15) 22% (9) 63% (8)
White 48% (94) 83% (12) 28% (36) 65% (20) 59% (17) 33% (3) 40% (5) 72% (18)

Obviously, a number of those sample sizes really aren’t large enough to draw any meaningful conclusions, but we can see that Johnson’s 44% success rate would’ve been at least a little higher (45%) had he and White split carries by down-and-distance equally.  By comparison, White’s would’ve been 48.6% compared to his actual 54% success rate.

What was CJ’s success rate in 2009?  Well, overall, it was the same 45% rate we would have expected if he’d gotten every carry in 2009.  As I have done in my posts on here looking at the offense, in this data set I’ve only included the post-bye week games, since I believe they provide the best look at what we should expect from the Titans in 2010.  In those 10 games, it was 45.8%, broken down like follows:

1&10+ 1&<10 2&7+ 2&4-6 2&<4 3&7+ 3&4-6 3&<4
Johnson 48% (132!) 22% (9!) 37% (51) 59% (17) 60% (20) 17% (6) 38% (8) 76% (17)

!’s to indicate the same number of carries as in 2008 for that down and distance, not factorials.  With exactly the same carry mix as in 2008, CJ would’ve had a better success rate-46.7% with every carry, or 45.4% with his actual carry mix.  As you can see from the numbers, he was particularly less effective in 1&<10 situations.  I expected those to be primarily -and-goal situations, but at FO we calculate a running back’s success based on expected inside the 5 and CJ came out exactly average.  Looking at the PBP, his biggest issue seems to be on carries from the 6-9, as he was successful only once on 6 carries.

Beyond that, though, there was no single area where he was significantly less successful than he or the Titans as a whole had been in 2008.  This suggests, then, that as a whole with a more normal level of booms like he had in 2008, the Titans running game should still be effective as it was in the playoff years of 2008 and of 2007, when White had most of the carries and a 46% success rate.  It likely won’t be as dramatically productive, but it should still rank among the league’s ten best.

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