Identifying Value in the NFL Running Back

Last week we looked at wide receivers and some various ways to look at pricing and value. This week I wanted to look at running backs but from an overall standpoint. Rather than just veterans we’ll also consider rookies here as we again look to answer whether or not it’s worth signing or using a high draft pick a running back.

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The Metrics

I wanted to break down the group into two primary categories. One is very simple- absolute production which is simply yards gained on the ground plus yards gained through the air (yards from scrimmage).

The second category looks at what I call player generated yards (PGY). PGY is an attempt to measure what benefit is actually brought by the runner and utilizing him to carry the football. To calculate this I’ll again turn to the raw statistics maintained by Pro Football Focus.

The way we calculate PGY is as follows:

(rushing yards- offensive line yards) + (yards per target/avg. yards per target)

I think rushing yards is pretty self-explanatory as is the yards per target portion of the equation.  For the middle part of the equation I am attempting to separate the performance of the runner from the performance of the offensive line. To do this we calculate the yards before contact (ybc) per attempt for each team and then compare the players ybc/att to his teams ybc/att on carries by other backs. This gives us some approximation of how much more worth he brings to the line than the others on his team.

For example 651 of Le’Veon Bells yardage came before contact, about 2.25 yards per carry.  The remainder of the Steelers roster averaged just 1.22 yards before contract per carry. Based on that figure we attribute 351.7 YBC to his offensive line and 298.3 to Bell. So Bell is considered to have generated 1004 yards on the ground and another 214 yards through receiving.

By no means is that perfect, and for players like Bell and DeMarco Murray who make up an extremely high percentage of their teams’ carries the numbers are going to be skewed more than others since we have such a reduced sample size of other players. But at least it can put the performance somewhat in context.

In terms of productive yards the top 5 players were Bell, Murray, Arian Foster, Justin Forsett, and Eddie Lacy (808). Once we factor receiving yards into it our top 5 is Bell, Murray, Lacy, Foster, and Marshawn Lynch. Players who generated the most production per opportunity (attempts plus targets) are Jeremy Hill, Bell, Lacy, Frank Gore, and Foster, among the higher use players.  On limited snaps Roy Helu was on top of the league, primarily from his passing game performance

Veteran’s vs Rookies

While for many positions there is a debate about expensive veterans versus cheap rookies, no position is as strongly debated as this one. Looking at the numbers it would seem to be a knockout blow that the rookie is the far better value player.

Veterans are producing at about a 20% higher rate than their rookie counterparts, but on a cost basis teams are paying nearly three times the cost in cap dollars for those veterans. On top of that it seems as if the added yardage is from teams simply giving veterans more chances with the football as they are basically no more or less productive than players who have been in the NFL for less than four years.

Our split is quite even with nine rookies and eleven veterans making up the top 20 in player generated yards and yards from scrimmage, so the veteran benefit is certainly limited.

Calculating Value

To look at value we are going to break the market down into two categories- veterans and rookies. For each category we will calculate the average salary cap dollar paid in 2014 for each productive yard and actual yard gained and multiply that by a player’s production to determine their actual worth in the year.

Here is the veteran market:

As we look at this model we are more less seeing that the maximum value in any given year that should be given to a running back is about $8 million and with that we are keeping our fingers crossed that we have a real workhorse player because if you get stuck with LeSean McCoy you end up with a major waste of cap space in a season.

Our average top 10 cap charge is $6.678 million and the average performance is worth about $1.56 million less than that. That should indicate a target value at the position of $5.2 million a year for the players projected to be the best in the NFL.

On the low end of the spectrum our true value is about $2.67 million, which I would think is the maximum value one can give to a projected low tier back. You may catch lightning in a bottle like with Forsett but it prevents you from getting stuck with a Toby Gerhart or Shonn Greene type.

Here is our look at rookie performance using the same criteria.

The reason our value numbers are so low here compared to veterans is because of the relative low cost of a draft pick. Murray, for example, would be worth around $9 million on the veteran scale because he is so much more impressive than a veteran player. But compared to this group of players it’s not realistic to expect.

As we look at rookies I think we are seeing a maximum contract value of just under $3 million for a rookie player, a number that is primarily based on heavy usage. If we consider both categories our max target will be $2 million. Our average top 10 performance based value is in the ballpark of $1.3 million.

The top 10 cap hits are $2.3 million though that number may be a bit skewed by CJ Spiller and Ryan Mathews playing under old CBA contracts, though it should be somewhat offset by the Trent Richardson trade. However the productive value of these players was under $800,000, making them essentially worthless picks. The value of the bottom 10 players, all basically playing at the $420K minimum was $648,000.

So how do we use these numbers?  In looking at the max values it would indicate that the highest any running back should be drafted is around number 25 overall and even that is a risky pick. In general teams should hold off on players until the 8^th or so pick of the 2^nd round to minimize your waste at the position.

Summary

I’d say the trends that we are seeing in the NFL right now certainly correspond with the performance. There is still some dead weight too clear out with veteran contracts that were signed a  few years ago, but teams are being safer now than before.

I think the main takeaways here are for teams to

1. Strongly consider letting free agents walk away if they will cost any more than $5 million a season over the expected contract life
2. Hold off on drafting running backs until the top 10 of the second round is complete
3. Don’t be fearful of drafting backs in the 3^rd and 4^th round in hopes of finding a gem in UDFA.
4. Don’t overpay low tier veterans just because its “cheaper than the alternative”. It’s still throwing money away especially when signed for more than one year.
5. Identify veterans that will sign for $2 million or less that may have something left in the tank it may be worth the risk.

For free agents like Murray, Mathews, and Spiller teams need to proceed with caution. Bringing Murray in below the values of players like McCoy and Matt Forte may seem unfair, but it is the smart move for a team to make to protect their downside since the upside is so limited. For the latter it’s going to be low cost contracts to minimize the risk.

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