Why the Arizona Cardinals Should Keep Feeding David Johnson

Arizona Cardinals rookie running back David Johnson has the eye of the tiger going into the final countdown of the season.

My generation may have been the first wave of kids who competed in organized athletics, with winners and losers, and yet received just participation trophies for their efforts. I’m all for awarding children on an even keel. Building up emotional strength and resiliency is important for young people, and sometimes kids do need to be reminded that playing for effort – the process – is just as important as winning, the product. That said, when we’re talking about professional athletes, I want to know who was the king of the hill. Which player is the absolute best among them?

For 2015 running backs, that may be the Arizona Cardinals’ David Johnson.

Now, I'm not saying that Johnson has anything on Adrian Peterson (who leads the league in rushing yards), Devonta Freeman (who leads the league in rushing touchdowns), or even Danny Woodhead (who leads running back in receiving yards), but Johnson has been terrifyingly efficient with every single one of his touches. Consider that, entering Week 13, Johnson had accrued seven offensive touchdowns on just 35 rushes and 29 targets. That kind of per-play upside is ridiculous, and now we're seeing if he can carry it over when given a full complement of opportunities.

Break out the blue ribbons, because Johnson’s per-play production has been championship caliber.

I Could’a Been a Contender

We all know David Johnson’s origin story: an exceptional runner with great quicks but underwhelming physicality on inside runs from the University of Northern Iowa fell to the third round of the 2015 NFL Draft. There, he was selected by Arizona and seemed to be the guy they would groom to be the future lead back of the team. The table below shows Johnson’s NFL Combine metrics and the percentiles his performances in each rank compared to running backs since 1999, per  MockDraftable.

Height Weight Hand Size 40 Yard Vert Jump Broad Jump 3-Cone Short Shuttle
6’1” (73rd) 224 lb. (76th) 9 5/8” (75th) 4.50 (67th) 41.5” (97th) 10’7” (95th) 6.82 (86th) 4.27 (41st)

Johnson is surely a physical specimen, albeit one that needed to develop in the league for a while. For this season, though, those who liked Johnson were hoping at least for a power back job in a timeshare with incumbent Andre Ellington. Instead, of course, the Cardinals signed Chris Johnson out of free agency, a move many thought would either be for depth at the position or would be an ill-fated experiment that would bust early on. It wasn’t, and it didn’t.

Chris Johnson’s presence on the team forced Ellington into a change-of-pace role and bumped David Johnson all the way back to a part-time third-down and kick return role. Throughout those 12 first weeks of the season, the rookie Johnson primarily rode the bench as the veteran one soaked up 20-25 touches a game. Yet, he still managed to accrue seven offensive touchdowns (eight, including a kick return touchdown on his first NFL touch of the ball).

So, why have the Cardinals kept Johnson at arm’s length until now, when both backs ahead of him are injured?


So, the Cardinals and fantasy owners now must entrust their fantasy playoff fortunes to the somewhat shaky hands of a rookie running back with just 89 career offensive opportunities. Can we be sure he’ll handle it well?

In Week 13, Johnson saw a whopping 22 rushing attempts and three targets, which he converted in 99 rushing yards and 21 receiving yards and a touchdown. Not too shabby for his first week as a bell cow. But how sustainable is this performance?

We can explore the value behind basic statistics with the use of numberFire’s signature analytic, Net Expected Points (NEP). NEP helps us take the numbers we get from the box score and assign them contextual value so they relate even closer to the game on the field. By adding down-and-distance value, we can see just how much each play and each team as a whole influence the outcome of games. For more info on NEP, check out our glossary.

The table below shows Johnson’s Rushing and Reception NEP totals (both raw and per play), compared to the veteran Chris Johnson and Andre Ellington’s, as well as each of their rankings among the 69 running backs with at least 55 opportunities through Week 13. Has Johnson been deserving of a bigger role?

Player Opps. Rush NEP Per Play Rec NEP Per Target
David Johnson 89 (54th) 1.59 (17th) 0.03 (12th) 25.84 (4th) 0.81 (2nd)
Andre Ellington 57 (t-66th) 6.48 (10th) 0.18 (4th) 10.52 (36th) 0.50 (17th)
Chris Johnson 209 (14th) -12.76 (58th) -0.07 (46th) 2.33 (62nd) 0.18 (58th)

First of all, we can rule out Chris Johnson as a big-time contributor in the future. He served a purpose this year, but is breaking down injury-wise and saw diminished efficiency as the year went on. He likely won’t be back in Arizona in 2016.

Clearly, Ellington has the most prolific Rushing NEP values of the three backs, but it’s important to note that he has one of the bottom-five opportunity totals for qualifying backs. We know that efficiency of value just flat-out diminishes with more touches, so it’s far to write off the slight difference in Rushing NEP and Rushing NEP per play ranking between Ellington and David Johnson. By looking at, also, we can see that while Johnson had a strong 4.5 yards per carry in Week 13’s game, he actually lost Rushing NEP, due to increased volume of touches and the inherent inefficiency of running the ball.

Where the rookie truly shines, though, is in his receiving ability. Part of that is that he has four touchdown catches – the top mark for a running back – but his agility truly shines in open space, as he can carve up a defense when given some room. In fact, this impeccable receiving skill puts Johnson seventh in Total NEP, and second in Total NEP per opportunity.

The Top of the Podium

So, if Johnson had received a greater volume of touches this year, would he still be as much of a metric marvel? It’s unlikely. Through the sheer inefficient nature of bread-and-butter inside runs in value analytics, a high-volume rusher will naturally lose a fair amount of NEP value over time unless they’re breaking off big plays frequently.

For Johnson, the big plays come through the air. He’s a versatile player, and one that that can rack up yardage on the NFL field and rack up points in the fantasy box scores in a variety of ways. That’s why you should continue to trust his success and keep rolling him out there in fantasy leagues. He’s good enough to keep his coaches happy in the fundamental part of the game and can flash some great upside on his catch-and-runs.

He may not be the best candidate to win the running back marathon for the 2015 season, but his mile splits are incredible. That’s worth a heck of a lot more than a participation ribbon to me.