The Arizona Cardinals selection of former Northern Iowa tailback David Johnson in the third round of this year's NFL Draft was met with much fanfare, and for good reason.

An absolute beast of an athlete coming out of college -- he was a top-performer in five out of six Combine events including a superb 4.50 40-yard dash time, 41.5-inch vertical jump, and 127-inch broad jump -- Johnson was tabbed by may as someone who could legitimately challenge talented but oft-injured Andre Ellington for lead back duties on this offense.

Head coach Bruce Arians, however, had other plans in mind.

When a hamstring injury sidelined Johnson early in camp this offseason, not only was Arians adamant in not giving his promising rookie touches if he missed training camp, but the team also went ahead and signed free agent running back Chris Johnson to be the new number two back in Arizona.

And just like that, David Johnson found himself tumbling down the depth charts before he could even step onto the field.

Yet, rather than accept his fate, David Johnson has instead made the most of his opportunities to show his team, the league, and most importantly, his opponents that they shouldn't sleep on him this season. And after a spectacular start to his young rookie season, as we'll soon discuss, it looks as though David Johnson is set to prove that regardless of coaching preferences, team situation, or experience, you can't can't keep talent off the field.

A Rising Star

So far Bruce Arians has made good on his promise not to hand rookies prominent roles on his team right away, saying he wants them to earn it.

And true to his word, over the first two weeks of the season, David Johnson has seen the field for just 21 snaps, touching the ball a total of seven times.

The result?

100 total yards and 2 touchdowns, including a game-sealing 55-yard score through the air on his only touch in Week 1 and a 13-yard rushing touchdown in the third quarter of Week 2. Oh, and that doesn't include his impressive 108-yard kickoff return for a touchdown to start last week's game against the Bears.

Not only has Johnson had some serious production in very, very limited playing time, but also he's done so in quite critical moments of the game, according to our Karlos Williams' 0.65 is a pretty distant second.)

Among 51 backs with at least 10 carries, Chris Johnson's Rushing NEP (-1.02) and Rushing NEP per carry (-0.03) rank 24th and 23rd, respectively. Ellington's cumulative score of -1.76 ranks 30th, and his per-carry mark (-0.15) ranks 38th.

With all that being said, it becomes clear that despite a lack of opportunity, Johnson has contributed more than his fair share to his team's success thus far.

What was that about rookies needing to earn a role on the team, Coach Arians?

Falling Competition

Based on his play so far, it's hard to argue that David Johnson doesn't deserve a bigger role on this team. Arians seems to reluctantly agree, saying his talented rookie should have a bigger role each week.

Yet, it's still hasn't been enough for David Johnson to leapfrog his veteran counterpart, Chris Johnson on the depth charts.

But if we're being fair, we should also ask if Chris Johnson has earned his current role as Arizona's lead back.

I understand the deference to the veteran to an extent, but as our Editor-In-Chief JJ Zachariason wrote prior to last season, the current version of Chris Johnson isn't even an average tailback.

Still riding the coattails of his 2,000-yard rushing season, since that year Johnson's productivity when compared to all backs with at least 200 carries over the past 15 seasons ranks him in the bottom-quartile of this group.

In other words, when you place David Johnson next to CJOverrated on the sidelines, you essentially get a ready-made DirecTV commercial with all that's missing Chris Johnson saying to the cameras, "I'm less talented David Johnson, and I have cable."

But ultimately, the question isn't whether or not David Johnson can surpass Chris Johnson in the Cardinals' pecking order. It's whether -- when and if Ellington comes back to this team at full strength -- David Johnson can pass incumbent starting tailback Ellington to be the lead dog in this backfield.

I would argue that the answer to this question should be a resounding yes.

Drafted in the third round of this year's draft, as JJ has said before, David Johnson is essentially a bigger version of Ellington.

And based on his play from last year, Ellington has done little to inspire confidence that he can operate as a lead back in the NFL to hold off the surging rookie.

Ellington had an abysmal 2014 season as measured by traditional as well as our own advanced NEP metrics. Among all backs with at least 200 carries last season, Ellington ranked dead last in Rushing NEP and Rushing NEP per attempt. And his Success Rate, which measures the percent of plays in which a player makes a positive contribution to his team based on NEP, sat at a laughable 33.83%.

Remember how bad we said Chris Johnson's efficiency was when compared to all tailbacks with at least 200 carries over the past 15 years? Well, Ellington last season was arguably worse than even him, with his -0.14 Reception NEP per carry ranking him 328th out of the 345 running backs with at least 200 carries in a single season.

Ellington supporters will point to his injured foot last season and use that as an excuse for his poor play in 2014. And while that may have certainly played a factor in his disappointing sophomore year, the signs that Ellington would not be able to handle a heavy workload were present even in his breakout rookie season.

When we look at his 2013 season and track Ellington's yards per carry on a per-touch basis over the course of a game, we see that his efficiency took a nose dive when his yards per carry over his first 10 touches are compared to his averages over the next 10. All this suggests that an increased workload for Ellington may not have been the right choice for him. 

Just to play Devil's Advocate, let's say we can blame Ellington's down 2014 season entirely to injury. That still doesn't mean he'll be effective in 2015 if he can't stay healthy. As Bill Parcells once said, "a football player’s best ability is his availability," and so far, Ellington's current PCL sprain isn't doing him or his team any favors.

With David Johnson measuring in as a bigger, stronger, faster version of Ellington, it's obvious that the rookie not only has the skill to take on the lead back role Ellington currently holds but also has the prerequisite size and strength to carry the workload that comes along with it.

Conclusions

From what we've just discussed, it's clear that, so far this season, veteran backs Chris Johnson and Ellington have done little to justify their time on the field, while David Johnson has shown that he has far too much talent to keep him off of it.

And if David Johnson can continue to impress the coaching staff and convince Arians he deserves a larger role on this team, the rookie tailback out of Northern Iowa might just become the most valuable player in this backfield sooner rather than later in terms of fantasy (as well as real life) football value.