The Value of NFL Runningbacks

Runningbacks have been an enigma is the NFL as the league has transitioned more and more towards passing the ball. There are high profile runningbacks every year that seem to be able to run efficiently and be helpful in the pass game, but then they disappear in only a few years. Yet, some runningbacks continue to sign massive contracts. As passing in the NFL has become more commonplace and more efficient, the place of runningbacks has come into question.

The Run Game

The first step in examining the importance of runningbacks in the NFL today is by exploring the trends in running offense from the past few years. First, we can see how the playcalling for offenses has changed since 1980. The rush percentage for NFL teams (Rush percentage = rush attempts / total plays) has decreased significantly since 1980, as teams in the 2010’s run the ball about 44% of their plays, down from above 50% before the 1980’s. Despite this, rushing efficiency has increased, reaching an all time high of 4.4 yards per attempt in 2018. While the increase in efficiency could be due to the decrease in rushing tendencies (runners have to run less which allows them to be more efficient when they get their chance), it could also be due to players naturally getting better. For example, passing efficiency has also boomed since 2000, as passes today have an average yards per attempt of 7.0 compared to about 6.3 in the early 2000’s.

Consistent with the rises in rush efficiency and pass efficiency, the average points per game for NFL teams has also increased steadily. It is difficult to tell if the decrease in running attempts is the primary reason that scoring has gone up using yearly trends, so exploring for each individual team over the past few years should give a better idea.

The sample for the graph above includes all offenses from 2010 to 2019. The smoothed trendline shows that teams that have run the ball more often have actually won more than those that pass more frequently. While this provides evidence for the importance of running, it could also be due to the fact that teams that are leading run the ball often late in the game in order to run the clock. However, the difference between the correlation of run attempts to wins from pass attempts to wins probably means that running does have importance.

While passing more frequently does not correlate strongly with winning games, having a high passing efficiency does have a relatively strong correlation with winning games. Moreover, the importance of pass efficiency to winning games is much greater than the importance of run efficiency, as there is a very low correlation for run efficiency. Therefore, it can be concluded that running is important for winning games, but how efficiently teams run the ball is not as important.

Paying Runningbacks

Despite the decrease in the value of runningbacks in recent years, some players such as Christian McCaffrey, Alvin Kamara, and Ezekiel Elliot have signed large contracts with an average salary of over $15 million per year. But is this the best way for teams to allocate their money?

Using the rushing stats and contract breakdowns from recent years, I constructed a scatterplot showing the relationship between the percent of cap space allocated to runningbacks and the team’s rushing production and efficiency. The graph on the left shows efficiency on the y-axis, where there is little to no correlation between cap percent and rush yards per attempt. The most efficient running teams have not needed to pay their runners significantly, shown by the Ravens in 2019 and Panthers in 2018. Moreover, the Packers in 2018 had one of the lowest allocations of cap space to runningbacks, using less than 1% of their cap space, but still rushed for over 5 yards per attempt. The same is true for rushing production, as the teams with the most rush yards per game over the last three years, which were the 2018 Seahawks and 2018 Ravens, used little cap space on runningbacks.

Another piece of evidence against the effectiveness of paying runningbacks would be the rushing production and efficiency of the teams that have allocated the most cap space towards runningbacks. The 2017 Steelers, for example, had about $12 million of their cap space dedicated to Le’Veon Bell, but they only ran for just above 100 yards per game. Furthermore, The 2019 Rams, led by Todd Gurley who had just signed a big contract, produced less than 100 yards per game.

There is little to no correlation between a high runningback payroll and rushing production, so NFL teams should try to avoid handing out large contracts to runningbacks. This is especially true if the runningback in question is not effective in the pass game, as some of the reason that players such as Christian McCaffrey and Alvin Kamara got paid so much was because of their contributions to the passing offense.

Another reason to avoid paying runningbacks is because they peak very early. Runningbacks are usually at their most efficient towards the beginning of their careers, while they are on their rookie deals and therefore are inexpensive. After age 24, most runningbacks see a large dropoff in efficiency along with a significant fall in touches at age 25. Since most runningbacks receive their second contract right around the age where their efficiency and involvement are expected to decrease, the value of these contracts is very low for the teams giving them out. Because highly paid runningbacks do not produce better rushing offense and runningbacks see a fall in efficiency and involvement early in their career, the best option for teams seeking a runningback should be via the draft.

Drafting Runningbacks

Now that I have concluded that the best strategy for rostering runningbacks is through the draft as opposed to paying free agents or extending current players, the next question is when to draft a runningback.

As the NFL has shifted towards passing more and more, the frequency of runningbacks drafted early has decreased. Only two runningbacks were drafted in the first round in the 2019 and 2020 drafts: Josh Jacobs from Alabama with the 24th pick in 2019 and Clyde Edwards-Helaire from LSU with the 32nd pick in 2020. The decrease in the frequency of runningbacks picked early is justified by the evidence of the lack of an association between draft slot and running efficiency. Runningbacks drafted in the first round are only expected to be slightly more efficient than those drafted in the later rounds. However, runningbacks drafted early usually have a greater amount of yards per game, although this is likely because they are used more and carry the ball more often.

The best way to find the optimal spot to pick a runningback would be to find where the largest drop off in efficiency is. As seen by the scatterplot of production above, there seems to be the most drop off in the early rounds, but it is not clear where production drops off most among the first four rounds. Similarly, it is difficult to determine where efficiency by pick falls the most as there is weak association.

To solve this problem, I looked at rushing efficiency by round. The runningbacks picked in rounds 1 and 2 have a similar efficiency, followed by a small decrease in round 3, then another drop off in the later rounds. Using the graph above along with the scatterplot showing draft pick against rushing yards per game, the largest overall drop off seems to be between the 2nd and 3rd round or the 3rd round and 4th round. Therefore, the best spot to take a runningback would be the 2nd or 3rd round. However, I would suggest that the 3rd round is the optimal place to select a runningback since it has already been shown that rushing efficiency does not matter a great deal and because selecting other positions likely have a greater benefit in the 2nd round.

Furthermore, the distribution of runningback awards by draft round agrees that the best place to take a runningback would be in the third round. All-Pro runningbacks have been selected in the third round at the latest; such examples include Jamaal Charles and DeMarco Murray (also Alvin Kamara, who will likely be an All-Pro this year). Additionally, there are falls in pro bowl rate and successful pick rate after the third round (a successful pick is determined by a player that sees over 10 touches a game).

While the difference of successful pick rate, pro bowl rate, and all pro rate all have a greater decrease from round 1 to round 2 than from round 3 to round 4, it does not makes sense to take a runningback in the first round. This is because of three reasons. The first is that rushing production does not correlate strongly with winning in the NFL, and the second is that other crucial positions, like quarterbacks or linemen, would be better options for a first round pick than a runningback. For example, in 2017 the Saints were able to pick three solid players (cornerback Marshon Lattimore, offensive table Ryan Ramczyk, and safety Marcus Williams) before selecting their soon to be All-Pro runningback Alvin Kamara in the third round.

The third reason to avoid drafting runningbacks early relates to the previous section of cap space allocation. Runningbacks drafted in the first round already are virtually guaranteed to make between $2 million and $6 million per year. Most runningbacks don’t make $2 million per year, so a first round pick is already more expensive than the median runningback. Meanwhile, third round picks have the possibility of making less than $1 million per year, making them even better value picks for teams. In contrast, a first round quarterback selection is a very high value pick since they make far less than most quarterbacks on the open market.

Conclusion

While the NFL has moved increasingly towards pass-first offenses, the running game has kept its importance. Rushing efficiency does not matter greatly, evidenced by its low correlation with winning, but rushing attempts are important since teams that win more often run the ball more often.

Because of the relative unimportance of rushing efficiency, teams should avoid paying or extending runningbacks. Players at the position often see a large fall in both involvement and efficiency after their first 3 to 4 years, meaning a second contract would provide low value. Moreover, there is no evidence that allocating more cap space towards runningbacks results in better rushing production or efficiency. Many teams, such as the Rams with Todd Gurley and the Jets with Le’Veon Bell, regretted their decisions of extending or signing a runningback quickly, leaving them with dead cap space and less wiggle room for years to come.

Since paying or extending runningbacks is not a good idea, the best source for runningbacks comes by the draft. Rushing efficiency and production see a significant decrease after the first three rounds, meaning that a third round pick would be the best spot to draft a runningback. Even though a runningback picked in the first round will likely be better than one picked in the third round, the rookie contract for a first round pick automatically is an expense, whereas the rookie salary for a third round pick is great value. NFL teams that are trying to evaluate runningbacks should realize that rushing attempts matter more than rushing efficiency, paying runningbacks is a bad idea, and the best place to draft a runningback is in the third round.