Does Pass Protection Prowess Help Running Backs in the Receiving Game?

When evaluating players’ production in the NFL, especially that of running backs, we talk a lot about “opportunity”. If a player has the opportunity to play or start, they instantly become much more interesting and valuable. The running back position has even become one in the league that, if a player has lesser caliber talent, as long as they have some window of opportunity, they will often be more highly lauded and valued. This has become the NFL talent evaluators’ Holy Grail; if we can figure out who has the most chances to play in any given situation, we know exactly how to project their production.

The unfortunate problem is we haven’t figured out that magical cure-all yet. We still hunt for ways to track player opportunity and what factors really play into added value. One of those factors has been that playing time will result in more chances for production - “the more you’re on the field, the better your chances to produce”. The logic is intended to indicate that if a player is a good blocker they will be on the field more on passing plays, and therefore will have a better chance to contribute more as receivers. This is what we'll examine in the case of the running back. Does good pass protection make for better opportunity for running backs in the NFL?

Building Blocks

Many people cite Knowshon Moreno's pass-blocking prowess as the primary rationale for why he was given the starting running back job in Denver in 2013. This ability would likely directly correlate to his production last season as well, then. Similarly, we believe that Lamar Miller got blown over in pass protection, and this is why the much less talented Daniel Thomas often relieved him on passing downs. Therefore, Miller’s value as a runner should have suffered. Is this a fair judgment to make?

We ground all of our research here at numberFire in our Net Expected Points (NEP) metrics. Simply, this is a measure of how much a specific player’s contributions better his team’s chances at scoring on any given drive. By comparing our running backs’ blocking and their NEP scores, we should be able to glean some bits of knowledge about the interplay of these measures of effectiveness in the backfield.

I looked at our Reception NEP and Target NEP metrics – the value each player added or detracted specifically on plays with a successful reception and any time they were targeted, respectively – as well as raw receiving statistics (receptions, targets , yards), and compared them to Pro Football Focus’s pass blocking grades to see if there was any correlation between them. This study mirrors an earlier examination I did of tight end blocking leading to receiving production, which you can reference here. The one alteration I made to this process is also comparing these receiving numbers to total snaps that each player had a pass blocking assignment, as another data point.

Stand and Deliver

There were 55 running backs who qualified for this study, having been on the field for 25% or more of their team’s 2013 offensive snaps. Of these players, there were heralded receiving options, such as Jamaal Charles, and infamously stone-handed players like Chris Ivory. To compare trends across this entire population of backs, I calculated the correlation factors between each receiving statistic and Pro Football Focus’s blocking grades. The table below lists these statistics along with their level of correlation.

Metric	Correlation Factor
Rec. NEP	-0.068
Target NEP	-0.066
Receptions	-0.108
Targets	-0.089
Receiving Yards	-0.081

To give some context to these correlation factors, anything below a 0.20 factor can be considered statistically meaningless as far as any relationship. 0.20-0.39 is considered weak to moderately correlating, but even this doesn’t suggest a direct cause-and-effect. In our study, none of these factors come anywhere close to the threshold for statistical consideration, indicating that blocking ability has nothing to do with raw production or even value of production, as indicated by our signature NEP metrics here at numberFire. To see if there were another way to break this down, however, I also compared these receiving statistics to total blocking snaps for running backs. These turned out in a greatly different way.

Metric	Correlation Factor
Rec. NEP	0.102
Target NEP	-0.037
Receptions	0.231
Targets	0.230
Receiving Yards	0.222

One can see easily that the correlation of blocking snaps to every production statistic immediately leapt into “weak to moderate correlation” range. This doesn’t indicate that there is a certain cause-and-effect scenario, but it does suggest that the more snaps a player is in, the more likely they are to be a contributor. In all honesty, though, these correlations should be much higher if there was a real relationship between blocking snaps and receiving, because one would expect a direct result of being on the field to be added looks in the passing game. Value, as in the blocking grades, can be a bit objectively viewed and not directly rewarded, but opportunity should lead directly to results if our theory is true.

The other sort of damning consideration is that neither grade value nor pure opportunity has any impact on the cumulative value these players put forth in the receiving game, as indicated by our NEP metrics. Neither their value relating to targets or receptions had any meaningful correlation to the time spent on the field.

Last Line of Defense

So, we’ve discovered that there is absolutely nothing to the idea that better pass blocking backs create more value in the receiving game. We’ve also seen that there is little to indicate a real relationship between opportunity in passing situations and added production as receivers. Where does this leave us? One last theory I tried out was that better (or more well-used) pass blocking backs might have more production or value in the rushing game. The idea is that if the quarterback audibles out of the pass, the running back on the field will take advantage of this and get extra carries. Even here there was no correlation to yards, rushing value, or total snaps on the field.

Where this seems to matter is not for lead backs, who are the focal points of the offense no matter what, but the change-of-pace players such as Giovani Bernard (9th in Rec. NEP; 4th in blocking grade), Roy Helu (25th in Rec. NEP; 3rd in blocking grade), and Andre Ellington (11th in Rec. NEP; 18th in blocking grade). These players may find coaches more willing to get them onto the field if they can be used in a versatile manner, and offer a more diverse skillset than the team’s “feature back”.

As for the notion of the blocking running back as a whole, though, it doesn’t seem to hold up. It seems that teams’ game scripts and designated assignments, not any player’s specific broad skill-set, tend to give receiving value to running backs. For instance, Darren Sproles has been one of the most prolific receiving backs over the last few years (39.65 Reception NEP; 5th among running backs), and his 2013 blocking grade ranked 33rd among our 55 runners. Similarly, Matt Forte had a breakout 2013 receiving campaign (43.78 Rec NEP; 4th among running backs), and he ranked dead last in our study in blocking grades. A player will receive offensive touches if they are a good offensive player.