Why Chris Johnson Could Actually Help the Arizona Cardinals Be a Better Rushing Team

Head coaches can sometimes do odd things to motivate players.

My high school basketball coach once threw a bag of orange slices off the locker room wall at halftime. Most of the pulp landed in my gym bag, so my clothes smelled of citrus for a few days. We still lost, I think, but the point remains.

He hated oranges.

That's probably not actually true, but the reason I bring it up is because coaches need to motivate players somehow.

When Bruce Arians, head coach of the Arizona Cardinals, suggested that he would be looking for outside help to improve the backfield play because Andre Ellington and David Johnson weren't doing well in training camp, it was unclear if this was just a head coach trying to motivate his ostensibly talented backs or if he was serious.

When rumors surfaced that the team had interest in Chris Johnson of the CJ?K variety, it didn't seem like a serious threat to Ellington's job security. However, the team agreed to a one-year deal with Johnson.

Now, even though Johnson  isn't any better than average, he might actually help improve the team's run game.

Here's why.

The Problem with Ellington

So, the way that we examine things at numberFire is through Net Expected Points (NEP), which indicates how a team or player performs relative to expectation level. A 15-yard carry does wonders to a yards per carry average, but if happens on 3rd and 20 and leads to a punt, it didn't really do much for the team. Conversely, a two-yard-carry is bad news bears for a yards per carry average, but if it's on 3rd-and-1 inside the red zone? That's a money play.

Over the course of a season, these plays add up, and that's not great news for Ellington.

Ellington's Rushing NEP last year was -28.34. That means he lost more than four touchdowns and extra points worth of scoring for the Cardinals with his 201 carries. That was the lowest cumulative Rushing NEP score in the league last year.

Darren McFadden (-22.48) was second-worst, and he was nearly a full touchdown "better" than Ellington, though he did run the ball just 154 times. Even still, Ellington's per-carry Rushing NEP (-0.14) was better only than McFadden's -0.15 among 32 backs with at least 150 carries.

In fairness, as a team, the Cardinals owned a schedule-adjusted Rushing NEP per play score of -0.05, which ranked them 26th in the NFL. And Ellington was banged up plenty. But when we're talking worst running back in the league territory, it's hard to forgive a guy just because of his name or small-sample success the year before.

That's a good segue. In 2013, Ellington posted a Rushing NEP of 7.01 on 117 carries. That ranked him 10th among 47 backs with at least 100 carries. Per carry, he ranked eighth. Not bad, eh?

But if we look at his Success Rate, the percentage of his carries that actually added to Arizona's expected scoring, we can see that he was -- unsurprisingly -- big-play dependent. His Success Rate of 40.17% ranked 30th among the 47 backs with 100-plus carries.

In 2014, his Success Rate (33.83%) ranked 40th among the 43 backs with at least 150 carries. That's not the recipe for a workhorse back.

A Rookie in the Mix

Arizona also has David Johnson, of course, a third-round pick from Northern Iowa. Johnson actually looked to have the potential  of a fantasy football pick this year, but his training camp couldn't have been much more of a letdown.

Johnson is recovering from a Grade 2 hamstring injury, and while the injury itself might not keep him out of the lineup come kickoff, his lack of practice time surely could.

Arians  said the missed practices are "killing" Johnson. If that wasn't clear enough, Arians also said, "There's no way in hell I'm putting him out there" early in the year if he misses training camp reps.

That's a big bag of welp.

Aside from Ellington and David Johnson, the team seems pretty content with Robert Hughes as the short-yardage back. But that leaves a lot of question marks between the 20's if Ellington can't start producing more consistently on his touches.

Chris Johnson to the Rescue?

Make sure you re-read that header un-enthusiastically.

Last year, the New York Jets ranked 13th in our Adjusted Rushing NEP per play metric, so they were much more efficient than Arizona's 26th-ranked run game. We do need to keep that in mind when comparing Chris Johnson's metrics to Ellington's.

Still, Johnson's Rushing NEP of -7.40 ranked 17th among the 32 backs with at least 150 carries in 2014. Per carry (-0.05), he ranked 21st. That's not great by any stretch, but it wasn't quite Ellington-level of bad.

As far as Success Rate goes, Johnson's 40.00% also ranked 21st in the group. It's not elite, but it's better than 33.83%. Perhaps the more worrisome part of the Success Rates is that, while both were lower than the team's collective rates (34.44% for Arizona and 42.53% for the Jets), Ellington was just worse at moving the expected points sticks than his strugglesome teammates.

Johnson's was still fairly respectable.

And to be clear, Johnson has posted some horrible Rushing NEP scores in his day, but never have they been as bad as Ellington's were last year -- even though both had their share of questionable offensive line play.

Johnson carried some big workloads in his day, but even with modest Success Rates, per-carry numbers, not-so-great offensive lines, and a home-run-or-bust mentality, Johnson never came close to losing 0.14 points with every carry like Ellington did last year.

I'm not saying that Johnson will make the Cardinals a good rushing team. But it's not much of a stretch to think that he could make them better given their current situation.