The Cardinals Spread It Out Like No Other Team. But How Much Is Too Much?

New Head Coach Kliff Kingsbury and Arizona have brought a variant of the Hal Mumme Air Raid to the NFL, and while the Cardinals didn’t earn a Week 1 win — they tied the Detroit Lions in their home opener — the system lived up to its billing. Known for its spread concepts and heavy use of the forward pass, the Air Raid relies on a smart, accurate passer to distribute the ball to a bevy of playmakers sent into routes that attack all areas of the field. And spread they did. With first overall pick Kyler Murray running the offense, the Cardinals trotted out more four wide receiver sets (45) on Sunday than the rest of the NFL combined (36).

Clearly Kingsbury isn’t afraid to be different, but it comes with risks. Going four-wide is an approach that hasn’t typically paid off for NFL offenses. In the 2017 and 2018 seasons, NFL teams ran 1,185 plays from four-WR sets and ended up stubbing their toes. Over that fairly large sample, the expected points added per play across the league was negative, at -0.03 EPA per play. Meanwhile, teams found success featuring fewer wideouts, averaging positive EPA per play numbers with their personnel groups of two and three wide receivers. As we saw, the Cardinals were responsible for the majority of those plays, though, so it’s encouraging they performed slightly better than the league mean, earning -0.01 EPA per play.

The Air Raid encompasses a set of passing concepts that many teams have integrated into their schemes, so it’s not completely new. Andy Reid of the Chiefs incorporated parts of the Air Raid into his system to suit the specific strengths of Patrick Mahomes, Kingsbury’s former QB at Texas Tech. But the difference for the Cardinals may be in the details. Kingsbury used wide splits and 3×1 wide receiver sets often to stress the Lions defense with his four wideouts, and Murray improved as the game went on. Perhaps they have what it takes to make four-wide in the NFL successful.

But we also wondered: Wide receivers aside, does a team having more eligible receivers running routes lead to more production in the NFL? Or do offenses benefit when players stay in to protect their QB?

Is adding more receivers to a play ineffective? Expected points added (EPA) per play by number of eligible receivers running routes, for 2017-18 regular-season plays Number of Routes Dropbacks Success Rate EPA per play 5 25,739 44.8% +0.04 4 9,419 44.9 +0.07 3 2,672 45.0 +0.12 2 or fewer 1,201 39.0 -0.03 Source: ESPN Stats & Information Group

Based on success rate and EPA per play, the optimum number of receivers to send out into routes is three. NFL rules dictate that five receivers at most can report as eligible to catch a pass on any given play, so this finding would appear to support passing out of heavy sets with big tight ends staying home to help shore up the pass blocking. Or perhaps teams should keep a running back in the backfield to help chip rushing defenders. But it also could be that those heavier sets are effective because of the deception they afford via the play-action pass.

To find out, we broke out all plays by the number of receivers and then split the plays by play-action and non-play-action. When we look at the plays this way, we find that play-action accounts for all the efficiency we see from the plays with three or fewer receivers. When play-action snaps are removed, passes with three or fewer receivers have a negative expected value leaguewide.

Play-action is more effective, especially with fewer receivers Expected points added (EPA) by the number of eligible receivers in route, for play-action plays vs. all other dropbacks, 2017-18 regular seasons play-action non-play-action Routes dropbacks success rate epa per play dropbacks success rate epa per play 5 2,753 49.0 +0.15 22,482 44.3% +0.03 4 2,783 50.6 +0.21 6,171 42.5 +0.01 3 1,438 48.8 +0.22 1,130 40.3 -0.01 ≤ 2 423 53.6 +0.42 764 38.3 -0.05 Source: ESPN Stats & Information Group

If your goal is to fool your opponent into thinking you’re going to run the ball, bringing in a bunch of players who look like blockers is probably a good idea. That’s an intuitive finding that makes sense. Meanwhile, it’s also heartening to see that adding eligible receivers to the route design of a non-play-action passing play leads to greater passing efficiency. That’s also a finding that we’d expect — the more passing options the better!

It’s no surprise that play-action continues to show up as one of the most efficient play types in football. Analysts have been calling it the NFL’s corner three for years. But it’s still somewhat shocking to see just how pervasive and massive an effect a little deception can have on the success of an offense. It will be interesting to see how much play-action the Cardinals incorporate into their attack moving forward. With a healthy dose, along with the ability to successfully flood the field with wide receivers over the course of 16 games, Arizona shouldn’t stay near the bottom of our Elo rankings for long.

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