For those of you who weren’t aware, beginning in 2016 NFL players had RFID chips put into their shoulder pads, allowing for a variety of things (like speed, location, or movement-path) to be measured. In the second half of the off-season they began rolling out some of these measurements on NFL.com and after going over the data myself, I thought it’d be fun to explore the data of Chargers players (specifically, skill players) with BFTB readers.
I will explain the various metrics as necessary, but I encourage you to check out more detailed explanations in the official glossary. Many of these metrics we’ll be looking at are more interesting than meaningful (at least in the vacuum they’re presented in), but I think it’s fun to explore. They can give us a little better look at the styles & schemes run by the various NFL teams.
First off, let’s talk about QBs. There were 5 metrics that caught my eye: Time to Throw, Intended Air Yard (avg), Air Yard Differential, Aggressiveness, and Air Yards to the Sticks. Philip Rivers finished 22nd (of 33 QBs with 200+ attempts) in time to throw, at 2.65 seconds average. This is a neat metric, but I’m disappointed that this only measures time on attempted passes (ie: not including sacks, which would help paint the picture of who holds the ball too long).
Next, Rivers finished 17th in intended air yards – also known as average depth of target. On average he was throwing the ball down the field 9 yards in the air. Now, this isn’t as good of a measure of style/scheme as breaking down attempts by % 1-5/6-10/11-15/etc yards downfield (though it’s simpler) but I still love that it captures some of the hidden information that normal statistics (even air-yards on completions) don’t capture. A QB may have an average air-yards/completion, but in actuality be passing deeper – we just can’t see this because his deep accuracy is below average. The NGS that helps show us this is Air Yard Differential: Intended Air Yards minus Completed Air Yards. Here, Rivers finished 11th with -2 yards (where 1st is the smallest difference and 33rd is the largest). This is not surprising as Rivers has always been one of the more accurate downfield passers in the NFL. The fourth metric is aggressiveness, defined as the percent of attempts coming when the target is 1 or fewer yards away from the nearest defender (at the time of the catch/incomplete). Aggressiveness isn’t inherently a positive or negative attribute, but I do think it’s eyebrow raising when a passer is ranked very low (are they only waiting until the receiver has an uncommon level of separation? Not throwing with anticipation?). Here Rivers ranked 21st with 18.7% of his throws qualifying as aggressive.
Finally, for QBs, let’s talk about Air Yards to the Sticks. Like TtT, this is another metric I thought they shared only a partial picture - it measures how far past the first down line completed passes (only) are thrown in the air on 3rd down. I would argue that as a measure of aggressiveness/gun-slinging, it hurts itself by not including incomplete passes (since an aggressive passer would be taking more deep shots which are more likely to fall incomplete). Nonetheless, I think it’s a very cool metric and still tends to match up with the eye test, as well as matching up very well with IAY. Rivers ranked 15th here, with his 3rd down completions coming on average 0.2 yards past the first down marker. Of the 33 QBs, 13 throw it before the marker on average, so I think Rivers’ mark here is just fine. With an increased focus on the running game, I think Rivers downfield passes will be more numerous – which should excite everyone not only because of his accuracy there but because the top passing offenses tend to be mostly comprised of QBs in the top half of IAY.
Speaking of the running game! Let’s take a look at where Melvin Gordon falls in 3 different RB metrics. First up, Efficiency. This takes the total yards an RB ran across the field (measured by the chip) and divides it by the actual credited rushing yards gained – North/South vs scat-back measure if you will. Here, my attempt cut-offs were more stingy than the NFL, so (for ranking purposes) I looked only at backs with at least 100 carries, and at least 10 carries per game (in an attempt to weed out obvious “passing specialist” backs). Of the 32 qualifying backs, Gordon ranked 17th with a ratio of 4.08 (where lower = more North/South, 0.09 less (or more N/S) than average). The next metric is very straight forward: how often an RB sees 8 or more defenders in the box. (Though to be clear, it’s not clear whether it’s % of rushes, or % of snaps the RB is in the backfield).
There is a wide spread of values here, and they’re not always reflective of who you’d normally view as a great back or one who “signals an obvious rushing play” (ex: bruiser Carlos Hyde ranked 31st here). Gordon faced 8 or more defenders FIFTH most, or 36.22% of the time (which was 10.31% above the average). Lastly, we have another metric that can reflect on an RB’s “style” – Time Behind the Line of Scrimmage. Just the way it sounds, it measures the time between the snap and when the RB crosses the line of scrimmage. It confirms the “eye test”, at least in that the king of patience Le’Veon Bell ranks dead last (/most time behind the LOS, 0.39s longer than average). In Gordon’s rookie season there was a lot of criticism about his indecisiveness, but this metric seems to confirm that he made large strides here in his 2nd year. He ranked 8th here, with 2.55 seconds on average behind the line (0.15 less than the average) – quicker to the line than the average runner.
Finally, let’s take a look at receiving metrics for the WRs and TEs. If you thought you were going to make it through one of my articles without a table, you were wrong. (I wrote enough when it was 1 player for each group; with 5 players it’s time to condense it). I’ll give you the table first, and then explain the various metrics. (It should be noted, the ranks listed are ranks within that player's position group, either WR or TE (though they are listed together on the NGS page online)). All players from the online page were ranked, which is any receiver with 43 or more targets (97 WRs and 35 TEs).
Our first metric listed is Cushion – or how far off (on average) a defender is lined up across from the player. The most useful or interesting rating here is Travis Benjamin and his 7.6-yard cushion – 2nd in the league! When you’re ranked among players like Tyreek Hill (1st) or DeSean Jackson (4th), you know opposing defenses respect your speed. The fact that this stat doesn’t line up with how often a player is targeted deep, backs up the idea that it is measuring (at least for those topping the rankings) whether defenses view a receiver as a speed-threat. The next metric is separation, how many yards the receiver is away from the defender at the time of completion or incompletion. With the variables in role or strength of defender faced, there isn’t a whole lot to glean from these numbers alone.
Next up is Targeted Air Yards (aka average depth of target – why they chose a different acronym from the QBs, I don’t know). As with the QBs, I love that this stat can take into account the invisible yards that may have piled up with an inaccurate QB. It makes sense that deep threat Benjamin also is targeted the furthest downfield on average. You’ll notice, however, that Dontrelle Inman is the only receiver notably away from average on the above-average column. This is an adjusted metric of mine, where I used this listing of slot-snap% from PFF free preview (data weeks 1-13) to identify each team’s slot WR and find the average TAY of those with 50%+ of their snaps spent in the slot, versus under-50%. The average TAY for “outside” WRs was 12.7 yards, while only 9.2 yards for slot-WRs and I thought this warranted filtering these WRs out. (TE average is 8.4, as you can calculate using Hunter Henry or Gates’s numbers).
Despite spending 64% of his snaps in the slot, Inman was targeted relatively further down the field. (I’d imagine part of this was due to the lack-luster running game last season, resulting in longer 3rd downs and Rivers feeling most comfortable with Inman in those situations). AYD is the same as it is with QBs, taking in intended air-yards minus the completed air-yards, highlighting who had a higher% of their deep targets fall incomplete. As expected the deeper-targeted receivers had a larger difference – although it should be noted Antonio Gates ranked high (in difference) among TEs, despite an average target depth. (But, we can’t readily answer “why” without more information). Finally, we’ll end on the receiver’s % of their team’s total intended air-yards (prorated by me, to the number of games the receiver played – as I feel that’s more reflective of who the team intended to go to as their top target). This is the column the table is sorted by and you can see that while Tyrell Williams was our “top receiver”, he ranked only 31 among WRs. The median value of the top 10 WRs was 38.5%, leaving us to wonder if the Chargers without a true #1 last season.
In fact, the Chargers 27.7% leading value was ranked 27th among all teams (only BAL, SF, CAR, SEA & ARI were lower). Should he remain healthy, we could expect Keenan Allen, in spite of his tendency for short-targets, to heavily lead this category next year. One last thing that stands out to me is the disparity (in % and ranking) between Gates & Henry. Gates will forever hold a place in Chargers’ history, but last season Henry was the better blocker and more efficient receiver (3rd in DVOA!). He NEEDS to get a bigger piece of the TE-pie in 2017.