True Sack Rate (TSR): A film project to quantify sack production - Week 11 Update

Introduction

From a team perspective, all sacks are positive for a defense, but they can mean very different things for an individual pass-rusher making the play. Depending on a variety of different factors, player evaluation based on raw sack statistics can often be misleading.

Players can add a ‘sack’ on the stat-sheet after the quarterback handles the ball for too long (either due to great coverage or the QB failing to recognize the opening in the defense), as a result of a protection breakdown, by tackling the QB at the line of scrimmage, when they’re being blocked, or by soundly beating the blocker in front of him due to superior athletic ability and/or technique.

By differentiating and qualifying these different pathways to notching a sack into four different categories — using film study, charting, and a simple grading scale — we can gain valuable insight into which players are earning their production vs. which players are beneficiaries of fortunate circumstances.

True Sack Rate (TSR) is a project aimed at studying and charting every sack of the NFL season recorded by an edge-rusher (DE/OLB), with the goal of identifying which edge-rushers utilized the highest level of skill against the most difficult set of circumstances to record a sack. Through this process, we will be able to more accurately evaluate sack and pass-rush production as a whole for the edge-rusher position.

The TSR will provide us with each rusher’s “sack score,” based on a point system that specifies four different types of sacks and forced fumbles, as outlined below:

1.25 points: Rare High Quality (RHQ) Sack - A 1-on-1 win over a very good (Ex: Duane Brown) or elite (Ex: Terron Armstead) blocker due to the rusher’s skill, move(s) and/or athletic ability.

Example: (2019) Cowboys DE DeMarcus Lawrence beating Lane Johnson 1v1 with his signature cross-chop move for a strip/sack.

1.0 points: High Quality (HQ) – A 1-on-1 (or 1-on-2) win over an average (or below) blocker due to the rusher’s skill, move(s) and/or athletic ability.

Example: Chargers DE Joey Bosa stringing together multiple moves (side-scissors) to win 1v1 vs. RT Elijah Wilkinson.

.5 points: Low Quality (LQ) – A sack coming as a result of being unblocked or a scheme such as a twist or stunt, in which no special skill or move was required in order to record the sack.

Example: Broncos edge-rusher Bradley Chubb getting a free run at the QB due to a linebacker blitz occupying the left tackle.

.5 points: Coverage / Cleanup Sack – An effort sack coming as the result of excellent secondary work or a quarterback hanging onto the ball for too long.

Example: Former Vikings and current Ravens DE Yannick Ngakoue getting shut down by the left tackle before retracing and sacking the QB due to him holding onto the ball for too long.

Both a low-quality and coverage/cleanup sack are valued and should be viewed similarly, but the distinction between the two is another layer of context in the evaluation process.

.5 points: Per forced fumble (strip/sack) - Stripping the ball and creating an opportunity for a turnover is as valuable as getting a low quality or coverage/cleanup sack.

NOTE: Beating tight ends or running backs can still be considered a high quality sack if a special skill was used to defeat the blocker. A high quality sack can also still occur on a stunt/twist, so long as the pass rusher wins a 1-on-1 battle against a blocker.Example of a high-quality sack on a stunt: Chargers OLB Melvin Ingram using excellent lateral quickness, speed, and bend to cross the LG’s face.

There are eight additional categories I charted for each player on every sack that bring more context into the production and evaluation of the individual pass-rusher. The move the rusher used, whether they forced a holding penalty, the opponent, down/distance, and if the sack ended the drive are all valuable data points to help paint a clearer picture on their impact.

Notes:

- Only edge-rushers with ≥100 snaps OR ≥2 sacks were charted

- All stats are via Pro Football Reference.

- Half sacks were counted as full sacks if it was determined that the rusher beat the blocker and was going to likely take down the quarterback without the help of a teammate.

- Recorded sacks when the quarterback got back to the line of scrimmage and didn’t lose any yardage were not counted, because of their relatively limited impact.. All sacks I counted required at least a loss of one yard or more.

- If the QB dropped 10 yards or more behind the line of scrimmage and an edge-rusher got the sack, the rush was more heavily scrutinized to determine if it was high or low-quality. The threshold that QBs are given on nearly every drop-back is between 9-9.5 yards. Anything past 9.5 yards, and the angle becomes increasingly difficult and unrealistic for tackles to match vs. rushers. If the QB drops beyond that depth, it’s then his responsibility to step up into the pocket or evade the rush on his own. This is admittedly a gray area, which sometimes makes  it difficult to assign a grade. In those rare situations, I reached out to at least one outside expert for an extra set of eyes to get their opinion for clarity.

- Over the last two seasons there have been around 75 sacks per week with about a 1/3 of those from edge-rushers. The weekly positional breakdown of sacks can obviously vary, but that’s about the average of what I’ve been seeing so far in 2020. That means that over the course of a season, there are 1,250-1,300 total sacks and about 425-510 (25-30 per week) from edge-rushers that I will be studying and charting.

Week 11 Results & Findings

Listed below is every edge defender (4-3 defensive end or 3-4 outside linebacker) in the NFL with a ‘sack score’ of at least ‘4’ (effectively a ‘Top 30’ in sack score through 11 weeks). You’ll also see their snap count, snap percentage, average number of snaps per sack (Sack / Snap), and average number of snaps per HQ sack (HQ Sack / Snap).

• There’s a new column in the TSR debuting this week: Drive Kill %
  - This measures the percentage of sacks that ended drives, giving us another data point to assess how impactful each edge-rushers’ sacks are on the game.

• All six of Broncos OLB Bradley Chubb’s sacks have ended drives, making him the only player in the top 30 sack score rankings with 100% of his sacks being drive-killers.

• Browns defensive end (DE) Myles Garrett is still comfortably ahead of his peers in sack score despite missing Week 11 and has double the amount of high-quality sacks than the second-place rusher (teammate Olivier Vernon with five). Garrett has already been ruled out for Week 12 due to being on the reserve/COVID-19 list, giving the rest of the NFL’s edge-rushers an opportunity to close the considerable gap he has over them.

• Garrett’s teammate Olivier Vernon had the best week of any edge-rusher and exploded up the rankings (outside the top 30 to 13th) after a spectacular three HQ sack performance, including one RHQ sack coming against Eagles All-Pro right tackle Lane Johnson:

• Panthers DE Brian Burns jumped seven spots from 15 to 9 in sack score after a pair of sacks (1 HQ, 1 LQ) rushing over the left tackle. His HQ sack was this gorgeous inside-out stutter ‘ghost’ technique to beat Lions left tackle Taylor Decker around the corner:

• Some of you have asked about Saints DE Trey Hendrickson’s charting this season and why he isn’t ranked higher considering the official NFL sack standings have him tied with Myles Garrett at 1st with 9.5. Hendrickson has been the beneficiary of fortunate circumstances on most of his sacks this season with four of his 9 sacks being coverage or cleanup and three of the remaining five being low-quality, leaving just two as HQ. Hendrickson notched his second HQ sack of the season last week vs. Falcons left tackle Jake Matthews using a bull-rush, with the other recorded sack not counted by the TSR due to him tackling QB Matt Ryan at the line of scrimmage. Hendrickson is having a good season without a doubt, but up until this point in the season has not demonstrated the same level of pass-rushing prowess, skill, or moves as the raw statistics would suggest.

• Saints fellow DE Cameron Jordan exploded for three sacks last week against Falcons right tackle Kaleb McGary, but all of them were as a result of excellent coverage and Matt Ryan holding the ball for too long.

• There are only three edge-rushers in the top 30 sack score rankings that have played under 50% of snaps this season: Washington DE Ryan Kerrigan (4.5 score on 37% of snaps) Browns DE Adrian Clayborn (4 score on 31% of snaps), and Eagles DE Josh Sweat (4 score on 48% of snaps). Each of these players are maximizing the time they have on the field and are producing impressive sack production.
  
  Here are the top edge-rushers sorted by total HQ sacks (minimum of three):

  

• The top two edge-rushers in total HQ sacks are teammates in Myles Garrett (10) and Olivier Vernon (5), an amazing nugget made even more so by the fact that fellow teammate Adrian Clayborn has an additional three HQ sacks, giving the Browns a ridiculous 18 HQ sacks this season, just from edge-rushers. To give some context as how impressive that number is consider the second highest amount of HQ sacks from edge-rushers on a team level is the Chargers with seven (Bosa has five, Nwosu has two).

  The top 5 leaders in most sacks per snap (minimum of 250 snaps):
  1. Trey Hendrickson - 1 sack every 43.0 snaps (387 snaps)
  2. Myles Garrett - 1 sack every 49.2 snaps (492 snaps)
  3. T.J. Watt - 1 sack every 61.9 snaps (557 snaps)
  4. Emmanuel Ogbah - 1 sack every 65.0 snaps (520 snaps)
  5. Za’Darius Smith - 1 sack every 65.5 snaps (524 snaps)

  Top 5 leaders in most HQ sacks per snap (minimum of 250 snaps):
  1. Myles Garrett - 1 HQ sack every 49.2 snaps (492 snaps)
  2. Joey Bosa - 1 HQ sack every 75.0 snaps (375 snaps)
  3. Olivier Vernon - 1 HQ sack every 87.2 snaps (436 snaps)
  4. Josh Sweat - 1 HQ sack every 113.7 snaps (341 snaps)
  5. Derek Barnett - 1 HQ sack every 122.0 snaps (366 snaps)

• Both Josh Sweat and Derek Barnett are quietly having good seasons for the Eagles in terms of sack production, especially considering they are splitting time with each under 375 snaps so far this season. Sweat had a beautiful HQ sack last week vs. Browns stud rookie LT Jedrick Wills Jr. using a double-swipe move and has had some tantalizing flashes this year.

  

  Miscellaneous notes:

• An error was found and corrected on Eagles DE Derek Barnett’s chart, changing one of his HQ sacks to a RHQ sack (vs. Trent Williams in Week 4), increasing his sack score by .25 points.

• Barnett’s adjustment means there are now six total edge-rushers with at least one RHQ sack: Joey Bosa (2), Myles Garrett (1), Khalil Mack (1), Olivier Vernon (1), Uchenna Nwosu (1), and Barnett (1).

• Notable edge-rushers without a single sack yet this season are Melvin Ingram, Jadeveon Clowney, Celin Ferrell and Arden Key.

• Montez Sweat has 6 sacks and all are LQ.

• Ryan Kerrigan is only playing 37% of the snaps for Washington but is still making a notable impact on the quarterback, notching a sack every 39.7 snaps and a HQ sack every 79.3 snaps.

• Cardinals OLB Dennis Gardeck has only played 48 snaps this season but has managed to notch two HQ sacks (both against the Jets).