Data Entry: Self-Scouting Chicago’s 2017 – Defense

| February 6th, 2018

Chicago’s defense was generally good in 2017. We all know this. They finished 10th in total yards allowed and 9th in points allowed.

Let’s take the same approach we took with the offense.

Rushing Defense

Chicago’s overall run defense was solid in 2017; they finished 11th in rushing yards against, 12th in yards per carry allowed, and 9th in touchdowns given up. Now let’s break it down by different areas of the field.

Here’s the data for Chicago’s rushing defense in 2017. The line at the bottom is the line of scrimmage, runs are split into 7 zones, and attempts and yards per carry are listed for each zone, with ranks relative to the rest of the NFL in parentheses. The height of the bar is proportional to yards per carry, and bars are colored green for top 10, red for bottom 10, and yellow for middle 12. Note expected yards per carry varies by region, so the colors are relative to their peers in that region.

A few thoughts:

  • There were some clear changes here from what this looked like at the bye, when the Bears were halfway through the season. That makes sense given all of the injuries that forced different personnel to play down the stretch. A few noticeable shifts include runs to left end and the middle, which I’ll expand more on individually.
  • At left end, the Bears improved a good bit in the 2nd half of the season. Halfway through, they were giving up 5.4 yards per carry there, and their work in the 2nd half dropped by a full yard per carry. Some of that might be due to a small sample size (only 18 runs in the first half), while others might be due to personnel. Cornerback Prince Amukamara largely played on that side, but he missed a large part of the first half. Outside linebacker Pernell McPhee also played less there down the stretch, and replacing his lack of speed with somebody else might have helped.

  • On runs right up the middle, the Bears got noticeably worse. In the first 8 games, they gave up only 3.3 yards per carry, a number that plummeted down the stretch. I’m guessing that largely has to do with injuries to nose tackle Eddie Goldman and inside linebacker Danny Trevathan, though both eventually came back after missing some time. The Bears had a couple weeks after the bye with a MASH unit at inside linebacker, which might have hurt there.
  • It doesn’t seem like teams prioritized attacking one side over the other on the ground, which makes sense. The Bears weren’t generally better at defending one side than the other.
  • I have no clue what happened at right end there. The Bears were consistently solid to mediocre in run defense everywhere else, but absolutely awful outside to the right. And this isn’t something that cropped up after the bye either. I don’t know if that’s an indictment of Kyle Fuller and Eddie Jackson, who primarily played on that side, the rotating cast of linebackers who were primarily over there, or something else entirely. I’m tempted to blame Fuller and Jackson because neither of them played in 2016, when this wasn’t an issue. Most of the other players who were largely on that side (Mitch Unrein, Jon Bullard, Sam Acho, Leonard Floyd, Nick Kwiatkoski, Christian Jones) played snaps there in 2016 as well.
  • On closer look, blaming Kyle Fuller for the run defense on the right side seems fair. Pro Football Focus credited him with 21 missed tackles, the most of anybody in the NFL by a wide margin (2nd had 14).

Passing Defense

Likewise, Chicago was generally fairly solid defending the pass in 2017. They were 7th in yards allowed, 15th in yards per attempt allowed, 7th in sacks, and 18th in passer rating against. But when you break it down by different zones of the field, you see that there was quite a bit of fluctuation.

Here’s the data for Chicago’s passing defense in 2017. The number of plays, completion percentage, and yards per attempt are given for 6 zones. Each zone is colored according to the average of the yards per attempt and completion percentage (green = top 10, red = bottom 10, yellow = middle 12).

A few thoughts:

  • If I’m going to blame Fuller and Jackson for run defense above, I should probably credit them for pass defense here. Teams loved throwing to the right this season, but found very little success doing it. I very much hope Kyle Fuller is a Bear again in 2018.
  • Like with run defense, looking at individual stats can help provide support for region-based conclusions, and here they back up that Kyle Fuller had a banner year defending the pass. Pro Football Focus says he was targeted 199 times (most in the NFL by 10 targets), but only gave up 61 completions. That’s good for a completion percentage of 51.3%, which was 17th best among NFL CBs, and a passer rating of 69 (nice!), which was also 17th among CB. On the season, Fuller gave up only 6.1 yards per target, which aligns nicely with the low yards per attempt to the right side.
  • The pass defense anywhere but the right side is nothing pretty, but not all that different from what it looked like at the bye. Deep left got a little bit worse, but that’s likely just due to the small sample size in the first half of the season (only 10 plays). I don’t understand why teams kept throwing at the spots they weren’t successful instead of the ones where they were, but I’m not complaining.
  • The left side in particular is interesting to me. That’s largely where Prince Amukamara played this year, and it seems teams didn’t want to throw at him very often. There’s value in that, as it could indicate he did a good job most of the time, but teams found excellent success throwing there when they did.

Overall Takeaways

Chicago’s run defense was consistently solid to average almost across the board, except for right up the middle and outside runs to the right. In the passing game, they defended passes to the right very well but struggled everywhere else. Weirdly, teams kept targeting the right side over everywhere else.

Chicago’s defensive coaching staff is back largely intact, and the bulk of their defensive personnel should be the same in 2018. Thus this type of information can be useful when evaluating what types of improvements coaches want to make in personnel and/or scheme this off-season to fix problem areas.

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