The Most Complete, Data-Driven Breakdown of the 2018 Bears Pass Defense Available

The Bears had the best pass defense in the NFL last season, finishing 7th in yards, 1st in yards/attempt, 1st in interceptions, and 1st in passer rating against. Now I want to look at the performance of each individual player in coverage, using stats from The Quant Edge.

Where They Lined Up

Let’s start by taking a look at where the CBs lined up. I’m only looking at the CBs here because all of the LB are listed as “LB” and all of the safeties “FS” for pretty much the whole time, thus those designations aren’t particularly helpful.

Pretty much the only point I wanted to make here is that the Bears played their CBs in specific spots, not against specific match-ups. Kyle Fuller covered the left (right side from offense’s perspective), Prince Amukamara the right, and Bryce Callahan the slot. Toliver filled in for Prince when he was out hurt (and some for Fuller late in blowouts), and McManis for Callahan.

Of course, Callahan is now gone, so it’s worth noting that 89% of Buster Skrine’s snaps came in the slot in 2018. It’s reasonable to think that will be his role in Chicago as well, but he has played outside a good bit in the past, so maybe he moves if Fuller or Amukamara get hurt and the Bears like McManis or Duke Shelley at nickelback.

It’s also fair to wonder if new defensive coordinator Chuck Pagano will ask his cornerbacks to move around a little bit more. When he was the head coach in Indianapolis in 2017, no cornerback played more than about 90% of their snaps in one spot. That’s still mostly intact, but not the 98%/99% Fuller and Amukamara had.

Coverage Statistics

Now let’s look at how well each player did in coverage. The table below shows that data for every CB, S, and ILB who played a meaningful role in 2018 (OLB are excluded because they saw very few targets due to rushing the passer more than dropping into coverage. Yes, even Leonard Floyd). Positions are color coded to make tracking the table easier.

A few thoughts:

It makes the most sense to compare players within the same position, as different positional roles will make comparisons between, say, Kyle Fuller and Eddie Jackson difficult.
Looking at the CBs, Kyle Fuller stands out. For the 2nd year in a row, he was the most frequently targeted CB on the roster, and for the 2nd year in a row he was the CB teams targeted the least efficiently. Sooner or later I imagine they’ll learn to stop throwing at him so much.
Kevin Toliver did decently well when he was in, but he sure did get targeted frequently. He had the lowest number of snaps per target of any CB, and thus by far the highest yards/snap. Sherrick McManis also got tested regularly when he was in, but he held up very well.
New Bear Buster Skrine gave up the following stats with the Jets in 2018: 6.5 snaps/target, 63% completion, 7.4 yards/target, 1.1 yards/snap, 5 TDs, 0 INTs, and a 113.3 rating. The passer rating looks ugly, but it’s entirely driven by the TD/INT ratio. The rest of the stats wouldn’t look out of place among Chicago’s CBs. The one that stands out a bit is that he was frequently targeted, but he held up pretty well against those targets, similar to Fuller and McManis. It will be interesting to see how he fares when surrounded by better talent in 2019.
Looking at the safeties, I’m struck by the fact that coverage stats are more difficult to assess for this position, because they are often not the primary player in coverage when a ball is thrown near them. Thus they are credited with far fewer targets, and much of their job doesn’t show up statistically. However, it appears all of them held up similarly well based on what we can see here. That could indicate a limited dropoff from Eddie Jackson to Deon Bush, which speaks well to Bush’s ability to provide quality depth in 2019.
New Bear HaHa Clinton-Dix gave up the following stats between the Packers and Washington in 2018: 16.9 snaps/target, 67% completion, 8.0 yards/target, 0.5 yards/snap, 3 TDs, 2 INTs, and a 97.2 rating. He wasn’t targeted often, but his efficiency metrics when targeted look worse than any of Chicago’s safeties. Again, though, I’m not sure that these numbers hold as much weight for safeties as cornerbacks.
Looking at linebackers, I immediately notice that teams sure liked throwing it at Roquan Smith. It makes sense that they were testing the rookie, but he generally held up pretty well.
The same can’t be said for Nick Kwiatkoski. It’s admittedly a very small sample size, but there’s a reason he was benched fairly early in the season, and it wasn’t run defense.

Man vs. Zone

Now let’s look a little bit at how the defense fared in various types of coverage. The table below shows overall statistics for the pass defense in man, zone, and press, and then we’ll break it up by individual players in each of those looks.

A few thoughts:

Just like with Chicago’s QBs, we see a higher completion percentage and poor TD:INT ratio against zone coverage compared to man. Unlike with Chicago’s QBs, we don’t see a correspondingly higher yards/attempt in zone. This indicates that Chicago’s coverage was able to do an excellent job of forcing teams to check down against zone looks, which is exactly what a zone is intended to do.
They struggled a bit more in man and press coverages, giving up fewer completions but more yards per attempt, which indicates more big plays were there to be had.
The pass defense was still consistently good throughout, however. All three coverages saw reasonable completion percentages and more INTs than TDs.

Now let’s look at how individual players fared in each one of these coverages, starting with man. I’ll note that I excluded Nick Kwiatkoski here because splitting up 7 targets into smaller sample sizes doesn’t really make any sense.

A few thoughts:

Again, let’s compare mostly within position, starting with CB. It’s a small sample size, but McManis was really good in man coverage when he filled in for Callahan late in the season. He got tested frequently and stood out in a good way in pretty much every efficiency category.
New CB Buster Skrine really struggled in man coverage in 2018, giving up 9.6 yards/target and 1.5 yards/snap. He was better in zone and press, as we’ll see below, but those numbers are bad. The completion percentage was actually respectable – 57% – which means he gave up a lot of big plays when he did allow a catch. The Bears can only hope that better pass rush in front of him and safety play behind him helps clean that up.
Moving to safety, it looks like Adrian Amos gave up more completions, but Eddie Jackson gave up more yards (Deon Bush saw 3 targets, so I honestly probably should have left him out due to sample size). To me, that probably indicates Amos was mostly matched up with TEs and RBs who work underneath more, while Jackson took on assignments that stretched farther down the field.
HaHa Clinton-Dix was targeted far more than any of Chicago’s safeties in man coverage, with a target coming every 8.5 snaps. He held up pretty well though, giving up only 56% completion and 5.8 yards/carry. Hopefully he can replicate some of Amos’ success covering TEs and RBs in man coverage.
Danny Trevathan is really good in man coverage. Like, really really good.

Let’s move on now to see what this looked like for the same players in zone.

A few thoughts:

It’s interesting to compare how numbers change for positions relative to man coverage. CBs see the yards/target mark drop across the board, from a group average of 7.9 in man to 4.3 in zone. The completion percentage and target frequency don’t change, but the TD:INT ratio goes from 5:5 to 1:7. The CBs were awesome in zone coverage.
The LBs, on the other hand, saw a change in the opposite direction. The completion percentage rose drastically from 54% to 72%, and with it the yards/target from 6.0 to 7.9. They also gave up more TD and fewer INTs, going from a 0:3 ratio to 2:2. This makes some sense, as zones are designed to keep things underneath, which often means LBs are going to be the closest ones in coverage on short stuff.
In terms of individual performances, Kevin Toliver stands out among the CBs as struggling a bit in zone. It’s worth noting this is from a sample size of 6 targets, so it basically means he gave up one really big play in zone.
New nickelback Buster Skrine put up the following zone numbers in 2018: 6.5 snaps/target, 75% completion, 6.1 yards/target, and 0.9 yards/snap. The completion percentage is a bit higher than you’d like to see, but the yards/target is actually decent. It looks bad here by comparison, but cornerbacks generally give up a fairly high yards/target mark, and 6.1 is still well below the league average overall.
HaHa Clinton-Dix really struggled in zone in 2018, earning a target far more often than Chicago’s safeties (8.5 snaps/target) and giving up 71% completion and 8.6 yards/target between his time in Washington and Green Bay. Some of that might be due to different zone responsibilities than he’ll see in Chicago, but that’s certainly a bit concerning. Hopefully a better pass rush in front of him will help Clinton-Dix hold up better in 2019.

Finally, let’s look at how Chicago’s CBs did in press coverage. There are fewer players included here because LB, S, and Kevin Toliver didn’t really play any press coverage.

A few thoughts:

Prince Amukamara sure loves to play press coverage. He had more press snaps than the rest of the CBs combined. Overall, 40% of his coverage snaps were in press, while no other player was above 24%. This probably accounts for why Amukamara was so frequently penalized, which doesn’t show up in these stats. He picked up 8 penalties for 90 yards on the season, while the rest of Chicago’s CBs combined for 4 penalties and 40 yards.
Generally we see a fairly low completion percentage against press coverage, which makes sense given this should lead to tight, difficult throws. Yards/target marks are mostly pretty high, however, which means the Bears gave up some chunk plays here.
The one exception to that is Bryce Callahan, who clearly excelled at press coverage in 2018. He was targeted far less frequently than other players here, and still was far more effective when targeted. New nickelback Buster Skrine similarly excelled in his 78 press snaps in 2018. He was frequently targeted (6.5 snaps/target) but gave up 50% completion, 5.7 yards/target, and 0.9 yards/snap. Hopefully he can continue that success in Chicago.