Over the last three years, Chris Johnson has rushed 817 times for 3,367 yards, a 4.12 yards per carry average. Over the last three years, the Jets have had running back seasons where a rusher recorded at least 150 carries: Bilal Powell and Chris Ivory in 2013, and Shonn Greene in both 2011 and 2012. Collectively, in those four seasons, the group rushed 887 times for 3,647 yards, a 4.11 yards per carry average.
If you put a lot of stock in yards per carry as a metric, it would seem as though Johnson won’t be bringing much to New York in the running game. But today we’re going to take a closer look at the production of Johnson and the Jets back. And I’ve created some graphs that I think are pretty interesting.
Because Johnson has 817 carries since 2011 and the Jets backs have 887, we can’t just compare things on a carry per carry basis (i.e., 20th best carry for each). So instead, I’m going to look at their percentile ranks — i.e., how many yards they gained on X percent of their carries. This first chart looks at the percentile ranks for Johnson and the Jets backs over the last three years. For example, 22% of Johnson’s runs have gone for negative yards or no gain, while the 22nd percentile of Jets runs has been for one yard. In the table below, the X-axis represents percentile, and the Y-axis represents yards gained. In this chart, being higher is better, and the Jets green line is higher or even with Johnson’s blue line on about 75% of all runs. Then, at the end, things switch, with Johnson being more productive with respect to each group’s best runs.
Here’s another way to present the same information: I subtracted the amount of yards Johnson gained on his average X-percentile run from the amount of yards the Jets gained on that same run. For example, when looking at say, the 45th percentile of runs, the Jets gained one more yard than Johnson did on his 45th percentile run. The Jets backs are tied or behind Johnson all the way up until the 77th percentile of runs. When looking at each team’s best 10% of runs is where Johnson really separates himself:
So Johnson is the big-play back, and the Jets have the steady eddies, right? Well, not exactly. Johnson was not very explosive last year, and the Jets were much more explosive without Greene. For example, take a look at the next graph, which looks just at 2013 information. I’m using the same percentile rank concept, with Johnson’s line in light blue, Powell’s in green, and Ivory’s in black:
Powell actually takes the lead early on: for example, at the 30th percentile range1, both Ivory and Johnson are at 1 yard, but Powell is at 2 yards. Johnson does look a bit more likely to have a 5-8 yard run than either Powell or Ivory, but it’s Ivory who produced the most big plays. Last year, Johnson’s longest run was 30 yards and that was his only run of more than 25 yards. Meanwhile, Ivory had seven runs of 25+ yards, including five of 30+ yards, and two of over 50 yards. And he did that despite recording 97 fewer carries than Johnson in 2013.
Next, let’s just compare Ivory to Johnson based on average gain at each percentile: in other words, we take Ivory’s average yards gained at X percentile, and subtract from that Johnson’s average gain at the same percentile. As you can see, this chart is very favorable to Ivory:
Comparing Powell to Johnson looks arguably worse for Johnson: not only is Powell more successful throughout most of the range, but he also had more big runs (Powell had two runs of 25+ yards and a 39-yard run, despite 103 fewer carries).
All of this seems like pretty ugly data for Johnson. But how much of it has to do with the running backs, and how much with the offensive line? There’s no consensus at to which team had the better offensive line, although I suspect most would say the Titans had the better run-blocking unit.
According to Pro Football Focus, the Titans had the 4th best run blocking line in the NFL last year, while the Jets ranked 31st. Football Outsiders had a decidedly different view, however: they ranked the Titans 29th in power run blocking (the Jets 12th) and 19th in stuffed rank (the Jets 8th), although the Titans did edge out the Jets in adjusted line yards. Again, reasonable people could differ on the strength of the two units.
Tennessee had Michael Roos, Chance Warmack, and Andy Levitre all season; David Stewart missed four games, and Brian Schwenke and Robert Turner rotated at center. Johnson also benefited from playing with Craig Stevens and Delanie Walker, two tight ends who are excellent run blockers. The Jets line generally stayed healthy — D’Brickashaw Ferguson, Nick Mangold, Austin Howard, and Willie Colon each made 16 starts — although left guard was a disaster, with Brian Winters occasionally ceding snaps to Vlad Ducasse. Jeff Cumberland and Tommy Bohanon are clearly inferior blockers to the Titans’ tight ends, and I think the better argument goes in favor of the Titans line as the superior one, as well.
So does this mean Ivory and/or Powell were better backs than Johnson last year? Not necessarily. Looking at some advanced stats take us in a slightly different direction.
- Football Outsiders gave Johnson a DVOA of 1.5% (22nd) and a success rate of 46% (31st). Both members of the Jets duo looked slightly worse: Ivory and Powell produced nearly identical DVOA and success rate numbers (-8.3%, 44% for Ivory, -8.7%, 43% for Powell), with both looking pretty unimpressive relative to their YPC averages.
- Advanced Football Analytics (formerly Advanced NFL Stats) has a similar take. Ivory had a 36.8% success rate and an EPA of -0.02 per play, while Powell had a success rate of 33.2% and an EPA of -0.12 per play. Johnson, meanwhile, was at 38.0% and -0.02, respectively.
Ivory and Powell both averaged more yards per carry last year than Johnson, which was reflected a bit in the above charts. But both FO and AFA seem to think Johnson’s production was slightly superior. Of course, once you factor in the offensive lines of the two teams, I think that difference probably goes away.
Does this mean Johnson was a bad signing by the Jets? After all, New York already has two running backs capable of similar production. I’d say the pro-Johnson argument has three prongs.
- Johnson played nearly all of 2013 with a partially torn meniscus; that may absolve some of his lackluster production last year.2
- Despite that injury, Johnson has been remarkably durable throughout his career, a trait certainly not shared by Ivory (or even Powell). In fact, Johnson has never missed a game due to injury in his six-year NFL career.
- Perhaps most importantly, Johnson is the most dangerous of the three in the passing game. Ivory has five career catches in four years, while Powell ranked as one of Football Outsiders’ worst receiving backs in 2013. Johnson’s four receiving touchdowns last year were an outlier, but he’s clearly the best back of the three when it comes to catching passes. Offensive coordinator Marty Mornhinweg wants to have a running back who can make plays through the air — remember, the Jets signed Mike Goodson for that purpose last year — and Johnson certainly fits that bill.
What’s less clear is if he’s even the best runner on the team. At one point, Johnson was the career leader in average length of rushing touchdown; now, he projects as a solid but unspectacular back. The Jets already have two of those, but that doesn’t mean they couldn’t use a third, particularly one with a different skill set.