The New England Patriots’ Stephon Gilmore is widely considered one of the best cornerbacks in the NFL. Through Week 11, he had given up a 47.1 passer rating when targeted this year — to put that into perspective, a 39.6 passer rating is awarded to a quarterback who spikes the ball on every play. (Through Week 11, no qualifying starting QB in 2019 had a passer rating lower than 70.) Because of his prowess, offensive coordinators and QBs don’t even look his way: Of the 326 passing attempts against the Patriots this year, only 64 (19.6 percent) came against Gilmore.
When it comes to measuring this aspect of defensive performance, we’re only beginning to scratch the surface. That’s because individual defense is inherently difficult to assess: A player’s defensive impact may be more significant in the absence of activity, but we can only count things that do happen. To measure a defensive player, we’re always chasing ghosts, trying to count things that don’t.
But thanks to the NFL’s Next Gen Stats tracking data — and the impressive work of researchers such as Baltimore Ravens personnel analyst Sarah Mallepalle2 — we can visualize that absence of activity.
A useful example involves where on the field opponents choose to attack a defense. Every week, coaches huddle around game film, analyzing defensive schemes and players, planning how to exploit what they see. The results of that game-planning show up in the tracking data. Here are charts that show where every team’s pass defense was the most and least vulnerable in the first eight weeks of the season:3
The charts shown are scaled from blue to white and white to red, with red representing the locations where offenses attempted the most passes against the defenses, blue representing the fewest pass attempts and white representing the average number of passes. In theory, the blue areas are places where the absence of activity reveals defensive strength.
In practice, it’s more complicated to solve the problem than simply plotting the distribution of all passing attempts or completions. Some offenses pass in unique ways because of their schemes and the skill sets of their quarterbacks and receivers. Take the Seattle Seahawks, for example:
Seattle QB Russell Wilson’s pass attempts are skewed to the left.4 Why? This is likely because of the inability of D.K. Metcalf, the Seahawks’ rookie wide receiver and 2019 second-round pick, to run a full tree of routes. During the season’s first two weeks, he was targeted only while lining up on the left side of the field. Through the first half of the season, Metcalf had been targeted 45 times, and only 10 were on the right side of the field.
Given that the Seattle passing attack is skewed, we don’t want to penalize any defense’s right side5 just because those defenders had to match up against Metcalf. So to normalize for an opposing offense’s usual tendencies, I compared an offense’s pass distribution against the defense in question with that offense’s distributions against the other defenses it has faced during the 2019 season. We can consider the difference to be the defense’s relative effect on a typical offense’s gameplan.
Let’s take a deeper look at the Buffalo Bills.
The Bills defense has been outstanding, giving up 304.1 total yards and 197.8 passing yards per game through Week 11 — third best in the league in both categories. But we can see a clear disparity in how opposing offenses are attacking starting cornerbacks Tre’Davious White and Levi Wallace. White’s reputation and production seem to have discouraged offenses from throwing in his direction. So far this season, White has given up a 58.9 passer rating on 66 targets, compared with a 101.2 passer rating on 79 targets for Wallace.
The beauty of the Bills’ defense is that their star cornerbacks don’t “shadow” or follow specific opposing WRs wherever they line up. Instead, they mainly stay on one side of the field, no matter who lines up there. Through Week 8, White had lined up on the left side of the field for 97 percent of his snaps, and Wallace lined up on the right side of the field for 96 percent of his snaps.
Our chart reflects that, as well as which cornerback scares off opposing QBs and where on the field that is. Opposing offenses target the left side of the field significantly more against Buffalo (to challenge Wallace, the weaker corner) than when they play against other defenses.
This approach to analyzing defense assumes that teams react rationally to defensive weaknesses they see on tape. That assumption may not always hold true, but taking note of changing tendencies is still one of the best ways to look for those hidden absences of activity that are key to identifying good individual defense.
We still don’t know if these splits have any predictive power. But this is the next logical step in understanding passing: analyzing the horizontal level. At a minimum, these new visualizations provide an interesting new insight into how offenses change in order to attack defenses.
gfoster: (Geoff Foster, sports editor): NFL Week 14 was very odd in many respects (and the week isn’t over) with the Raiders, Niners and Giants winning and the Rams, Texans, Steelers and Patriots all losing. It all went a long way to making the playoff picture even murkier. What was your biggest takeaway from the week?
Salfino (Michael Salfino, contributor): How much should we be worried about the Rams? Is every offense entitled to one hiccup like this, or is it part of a pattern that began with the Lions, who did not care about play-action at all and just covered the receivers. The Bears also did not bite. Does Los Angeles have a Plan B?
neil (Neil Paine, senior sports writer): It was definitely startling to see the Rams’ offense be held in check so thoroughly. Jared Goff was terrible. Todd Gurley did next to nothing. The Rams’ offensive expected points added in the game was -23.5. That was 29.6 points worse than their second-worst offensive game of the season … which was Week 13 vs. Detroit. And it was 33.8 points of EPA worse than their low before the Detroit game.
sara.ziegler (Sara Ziegler, assistant sports editor): I know people talk a lot about playing in the cold as a problem, and I usually roll my eyes. But was that a factor here?
neil: The Rams have only played four games where temp was under 50 degrees in the Sean McVay era.
Salfino: I know, that temperature stuff. I just can’t believe these guys from all different parts of the country are suddenly able to only play in warm weather. But that’s going to be the theory of the case now almost certainly.
gfoster: The Rams game at Detroit was definitely curious. They came out of the bye completely flat, Goff played poorly, and most people kinda wrote it off to rust. But now I’m starting to wonder if teams, as Mike alluded to, are starting to figure out this McVay offense.
Salfino: This kind of thing has happened before. The 1994 49ers team that won the Super Bowl and was electrifying on offense laid an egg against the Eagles that year, losing 40-8. They had 189 yards that game.
And on defense, the 1985 Bears famously flubbed a primetime game against the Dolphins late in the year for their only loss that season.
gfoster: That Detroit game was in a dome, Sara.
Salfino: This can’t be Cooper Kupp, can it? My theory of playing the Rams was to just ignore the running game. I figured a team that gave them fits would basically concede Gurley. What really surprised me about the Chicago performance was that Gurley didn’t even get going. They had nothing. The Bears didn’t even accept the slow death of Gurley running.
sara.ziegler: But why didn’t the Rams even try to run Gurley? Only 11 carries?
neil: Good question, Sara. They had been almost exactly balanced (49.7 percent pass/50.3 percent run) on first down, but last night they passed on 73 percent of first downs. Despite averaging 4.6 yards per carry on the first downs where they did run.
Salfino: My feeling watching the game with Gurley is that the Rams wanted to get wide open passes by faking to Gurley like they usually do, and then when that didn’t work, they were behind the down and distance and had to straight-up pass, with typically disastrous results.
neil: Right — Goff had a 23.0 passer rating on 1st down.
Salfino: What happens to a play-action offense when no one buys into the deception? When the defense just ignores it?
sara.ziegler: I guess I would argue that you should just run the ball.
Especially with a guy like Gurley.
Salfino: Exactly right. That’s when they should run. This is probably why McVay was so hard on himself in the post-game.
sara.ziegler: I just need to take a second to thank Drake for giving me 12.2 fantasy points on that play.
Salfino: Fantasy scoring on that play is hilarious. It goes as a Tannehill touchdown pass. There were no screams about that because who’s playing Tannehill?
sara.ziegler: LOL, good point.
Salfino: How dumb are the Dolphins though for not getting a guy as electric as Drake the ball more on offense? But they’re 7-6. Have to be one of the worst winning teams at this juncture of the season in memory, but they do own wins against the Bears and Patriots.
gfoster: Salfino is not a Frank Gore fan.
Salfino: OMG, Frank Gore. The dude is a survivor, I’ll give him that. He’s going to end up in the Hall of Fame, too. But he’s been just a guy for so long now.
gfoster: Neil wrote about this recently. Is this Patriots team just not intimidating?
Gronk’s “defense” is getting the headlines, but he had a big game offensively Sunday. There’s no doubt the offense is world’s different when he’s healthy — and it’s hard to remember a playoffs when he was remotely healthy.
Salfino: The Patriots’ problem is that they lacked offensive upside. But then Tom Brady really looked like the Brady of old vs. Old Brady. Gronk got rolling. Gordon was hyper-efficient. The running game was trash, but that’s sort of old-school Patriots too. Even the defense struggling seemed normal. But losing that game was not normal at all. If you told me New England was going to lose, I’d figure it was their offense flagging the game.
neil: Although it’s worth noting they forced zero turnovers against a Tannehill Phins offense.
sara.ziegler: That’s sort of the beauty of those lateral plays actually working: It’s a fluke, not a systemic problem for them.
neil: But this is definitely the type of toss-up game they usually find a way to win, not lose.
sara.ziegler: For sure. Which is what made it so fun!
neil: At least for 31 fanbases searching for Patriots schadenfreude.
Salfino: I really thought one of the Patriots and Steelers would emerge in the AFC, and now maybe both of those teams are going to be playing wild-card weekend.
gfoster: There are four AFC teams at 7-6: Ravens, Colts, Dolphins, Titans. Which one of those is going to make the playoffs in your eyes? Or will it be the Browns, Neil?
neil: They’re “in the hunt”!
For the first time in approximately 30 years.
Salfino: I think the sixth team in the AFC will be the Colts. Andrew Luck is totally out of his shoulder issue and throwing the ball downfield. T.Y. Hilton has nearly 600 receiving yards in the past four games. Luck-to-Hilton is maybe the most lethal combination in football right now.
gfoster: Not Luck-to-Ebron?
neil: For what it’s worth, our model thinks the Ravens still have the best chance at 55 percent.
sara.ziegler: I like the Ravens. They were super unlucky to lose to the Chiefs.
Salfino: The Ravens did everything right on defense. Tyreek Hill takes standing eight counts with three different injuries. And you look up at the end of the game and Mahomes has nearly four bills and the Hill has 139 receiving yards. Spencer Ware looked very dangerous. How can anyone stop the Chiefs?
neil: The diagram on that one is amazing, too:
Patrick Mahomes' fourth down completion to Tyreek Hill on the @Chiefs game-tying drive had just a 15.8% Completion Probability based on the following factors:
Salfino: The Ravens blitzed the hell out of Mahomes, and it really seemed to give him fits, but then again you look at the stat sheet and are like, “??????”
gfoster: I would normally say here that the Chargers could hang with the Chiefs and look like the AFC’s Super Bowl-bound team. But that was a somewhat lifeless effort by them Sunday. Against Jeff Driskel and probably the worst defense in the NFL.
sara.ziegler: I guess we’ll find that out on Thursday, when the Chiefs and Chargers play.
Salfino: I thought it was going to be typical Chargers. But maybe typical Chargers is having easily the second-best team in the conference and somehow being the fifth seed. As for the Bengals performance, it fits the “letdown game” theory between Pittsburgh and Kansas City.
gfoster: Although, it should be noted that Mike Badgley hit four of four field goals, including a 59 yarder. That actually ties the total of made Chargers field goals for the last two seasons.
Salfino: How is Hill going to play that game on Thursday? He was like Rocky on the stool at the end of that Ravens game.
The thing about the Chargers that’s weird is their pace of play. They were 29th in plays before last week and then put up another relatively low play count.
Could Mike Tomlin get fired if the Steelers miss the playoffs? Should he?
sara.ziegler: Not in light of the Le’Veon Bell mess, I’m guessing.
Salfino: Has Bell’s absence even hurt the team? Sunday was the first game you could say they lost because of it, arguably. But the defense could not stop Derek Carr. Think about that sentence in the context of this year.
gfoster: I don’t think this Steelers team is very good. They now have the Patriots and then AT the Saints. They could easily be 7-7-1 going into final week.
sara.ziegler: I’ve been amazed all season at how high the Steelers’ Elo was. But they just kept winning — until the past three games.
neil: Looking at our Elo, though, the Steelers usually pick up steam late in seasons. They haven’t had a swoon like this since 2012.
And that year they could pin it on Charlie Batch starting some games.
Salfino: Explain to me how Roethlisberger goes 25-for-29, the Steelers defense is still near the top of the league in yards allowed per play, and they lose to the Raiders. Tomlin totally blows the end of the game by not calling a timeout, he gets his own lateral play to work, and then the kicker falls down.
Salfino: Steelers vs. Patriots is the game of the week, but not for the reasons we thought going into the season. These are two desperate teams now. The Steelers are teetering on elimination, and New England can’t win the conference without a bye, IMO.
Do you know how hard it is to pass like Roethlisberger has this year and have a top defense in yards per play and still struggle to win?
gfoster: They haven’t beaten a truly good team this season. Especially now that we can safely call the Panthers a bad team.
And the Jags.
And the Falcons.
The Steelers’ best win was arguably over the Browns!
Salfino: They really should have beaten the Chargers, though. But you’re right.
sara.ziegler: And they would have beaten Oakland, if not for their kicker falling down.
neil: … another really bad team.
Salfino: Are we worried about the Saints? They did not really bounce back at all offensively from last week’s loss to the Cowboys. You have had the feeling all year that Sean Payton was worried about the depth of his receiving corps, and they had nothing other than Michael Thomas on Sunday — and Thomas really had to grind it out. Nothing in that game against a terrible Tampa defense was easy, which is shocking.
gfoster: But on Thanksgiving, we were singing the praises of Brees’s ability to throw TD passes to four different guys who walked in off the street and put on Saints jerseys.
Salfino: I think the Saints defense is underrated now and the Saints offense is overrated.
gfoster: Where are Austin Carr, Keith Kirkwood, Tommylee Lewis and Dan Arnold?
Salfino: Arnold was inactive on Sunday. Crippling loss.
That quartet sounds like a country rock band lineup.
gfoster: He seems like he’s looking to run. You watch a QB like Watson, Rodgers, Mahomes — they are so reluctant to do it. Always have eyes down the field until they physically cross the line of scrimmage.
Salfino: My theory with Allen is that his running is so effective and reliable that it’s hurting his development as a passer.
gfoster: He also has the worst supporting cast of possibly any QB ever.
Salfino: Darnold escapes to throw and not run, too. Especially on his touchdown pass Sunday, which was an incredible play.
Salfino: Sara mentioned the Eagles. Is their window closing? They’re going to have to rebuild their defense, which is bereft of impact players. Their skill players are mediocre. Alshon Jeffery is not a No. 1 receiver, remotely. Suddenly their team-building seems suspect.
Salfino: The Cooper trade is going to go down in history as the best in-season deal. He was the missing piece. Everyone else is now in the role that they are suited to be in. Dak Prescott was explosive Sunday. I can’t believe I’m saying it.
The bug for the Cowboys was supposed to be their decision-making by Jerry Jones and his family, and that’s turned out to be their strength. Seriously, name the team that’s drafted better recently than the Cowboys. Now add Cooper to this. God, I hate myself for saying this.
gfoster: The issue with that trade was more relative to the wide receiver market. Golden Tate, Josh Gordon and Demaryius Thomas were all traded for a far smaller return. The difference is that prior to the deal, I would have lumped Cooper in with that tier of receiver, but it’s possible that his problem was even more Derek Carr than I thought.
Salfino: My view is that Cooper is an explosive player who can take the top off the defense. Those other guys, including Gordon now, cannot.
Salfino: Oklahoma somehow pulled a Favre to Rodgers in college football.
sara.ziegler: I’m still kinda shocked that Kyler Murray won.
It really came down to performances in the conference championships.
neil: It’s funny because the Tua-is-unstoppable narrative had been in place for like two months (or more). Yet the signs were there that Kyler was a legitimate threat to him. He had a better NCAA passing efficiency, better QBR. Betting odds even favored Kyler on Saturday AM.
Salfino: My take is that Alabama would be great/No. 1 in the country with pretty much a typical college QB, but Oklahoma absolutely must have Murray to rank where they are. So Murray is the MVP of college football for sure.
gfoster: Here’s the flip side of that: Tagovailoa barely played in the fourth quarter most of the season, while Murray was needing to score 40 to 50 points every week to beat any team.
Salfino: I’ve heard the draft people concede the Murray would be a first-round pick. Now the question I guess is how high? There are no rules anymore after Baker.
sara.ziegler: Unless he’s an Oakland A by that point…
gfoster: And, likewise, Mahomes coming out of the same Big 12 nonsense football that looks like two 11-year-olds playing Madden.
Salfino: If Murray is a top-five pick, the financial calculus changes dramatically. He may never get another MLB contract. Look at ninth-overall picks in history, for example.
Quickly give me the Week 14 Super Bowl prediction and No. 1 overall pick prediction, since we have a legitimate race this year.
neil: I guess I shouldn’t stick with my October pick of the Vikings…
They’re not out of it…
neil: Although who knows! We’ll see tonight.
sara.ziegler: I still think it will be the Chiefs out of the AFC, but who knows from the NFC.
Even after last night, I just can’t get behind the Bears.
gfoster: Sara, just pick the Vikings, it’s fine. We will forget about it.
sara.ziegler: I can’t. The moment I do, it’s over for them.
Salfino: I think the Raiders are the favorite for the No. 1 pick because San Francisco is going to face backups against the Rams in Week 17. I picked Saints-Steelers in the preseason. I will stick with the Saints — figuring that Payton figures it out. AFC has to be the Chiefs now. They do have a pass rush. They absolutely cannot lose Hill or Kelce though. (And obviously Mahomes.)
Betting on Andy Reid in January though and the Chiefs in January at home, yikes.
sara.ziegler: I’ll take a long shot for the No. 1 pick with the Jaguars. That’s a team that looks like it does not care.
neil: I will speak for the model and pick the Saints coming out of the NFC. We have them at 26 percent to win it all. AFC favorite is Chiefs, though I share Mike’s concerns there, despite my crush on Mahomes.
And I’ll go with the Cardinals at No. 1, our model’s pick for the worst record.
Forecasting the race to the bottom
Fewest projected 2018 wins according to FiveThirtyEight’s NFL Elo model
gfoster: I’m saying Saints over Chargers. Cardinals with the first pick (they have at Seattle and Rams still).
And if the Chargers get drilled by the Chiefs on Thursday, I will sneak into WordPress and delete all of this.