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Data Entry: Zooming in on Coverage Players (Corners)

| June 29th, 2022

 


Today we’re going to shift from examining players who rush the passer to those who defend passes that are thrown. We’ll start by looking at the CBs, with an upcoming article to look at linebackers and safeties.

In order to do this, I’m using data from Pro Football Focus (PFF) that looks at how frequently and effectively individual players are targeted in coverage. I chose to set a threshold of 250 coverage snaps because it both gives a decent enough sample size to judge an individual player and gives a big enough grouping of players at each position to evaluate how somebody performed relative to their peers. This threshold gave a sample size of 106 cornerbacks, or 3.3 per NFL team.


First Look

The Bears have four notable veteran cornerbacks: returners Jaylon Johnson, Kindle Vildor, Duke Shelley, and newcomer Tavon Young. The table below shows how they fared in a variety of coverage metrics last year, as well as their rank compared to 106 cornerbacks who had at least 250 coverage snaps. To give a broader frame of reference, the best, average, median, and worst values among that 106-player sample are also provided for each statistic. Categories highlighted in green indicated the player was in the top 25% relative to their peers, while red indicates the player was in the bottom 25%.

A few thoughts:

  • Let’s start with Jaylon Johnson, who is probably not as good as many Bears fans have made him out to be. To be fair to Johnson, he often shadowed the other team’s best WR in 2021, so quite a bit was asked of him, but his overall profile here shows a CB who is more average starter than great. Still, he is at least an average starter, and that’s something.
    • You can also see Johnson’s stylistic approach to CB show up through a few of the stats. Passes thrown at him are generally pretty deep because he plays tight man coverage and doesn’t give up easy stuff underneath. That leads to a low catch percentage, but also a high yards/catch value.
    • Overall, Johnson ends up around average in both yards/target and yards/coverage snap, which are probably the best 2 overall metrics to go to when evaluating CB play.
  • It’s a very different story for Kindle Vildor, who was the worst CB in the NFL in yards/target. Like Johnson, he likes to play tight coverage, which gives him a high average target and catch depth. Unlike Johnson, Vildor gave up a really high catch percentage, which is really bad when passes are deep. One good thing is that teams didn’t throw at him very often, but they were hugely successful when they did.
  • Finally, let’s take a look at Duke Shelley and Tavon Young, who have similar profiles because they both primarily play nickel. That means they see more short passes (low target depth and air yards/catch) but give up more catches (high catch %). Young was appreciably better at limiting yards after the catch, which meant his overall metrics (yards/target and yards/coverage snap) were around average, while Shelley’s were terrible.
    • It seems weird that Shelley was the worst CB in the NFL giving up yards after the catch despite being very good at avoiding missed tackles. That must mean many players who caught the ball had so much space between them and Shelley that they could keep moving without him having an attempted tackle to miss.



Man/Zone Split

Now let’s split up this overall data between man and zone coverage, as some players will do better in one than the other. The table below shows most of the same stats as above but split into when the player was in man (blue, top half) or zone (orange, bottom half) defense.

A few thoughts:

  • The first thing that jumps out is that all four cornerbacks were asked to play man defense among the most in the NFL. If we assume Matt Eberflus brings his defense from Indianapolis with him to Chicago, we can expect about 15% more zone, as Colts CBs in this sample played zone a total of 69% of the time in 2021.
  • With that in mind, I am a little more intrigued by Kindle Vildor than I was after the first table. Vildor was atrocious in man defense, but actually not bad in zone last year (as Andrew Dannehy pointed out a few weeks ago). I’m not saying he was all that good in zone, but he was generally average to below-average there, as compared to atrocious in man. Vildor is expected to compete for the top backup spot in camp, and I actually feel pretty good about him in that role for this defense.
  • Both Duke Shelley and Tavon Young see the opposite split, as they struggled much more in zone than man.
    • Young in particular was an elite man coverage CB, but really struggled in zone. In man, he had the great combination of mainly giving up short passes and then limiting opportunities after the catch, but he had a difficult time containing yards after the catch in zone.
      • It seems strange the Bears targeted Young for this zone-heavy defense, but perhaps that’s a reason why Thomas Graham has been taking most of the 1st string nickelback reps this offseason. Graham, by the way, only played 59 coverage snaps last year, which is far too small of a sample to take anything away from.
      • Injuries are also a real concern for Young, as 2021 was the first year he was healthy enough to play 50 snaps since 2018 (and he still missed half the 2021 season with injury).
    • Shelley may have been the worst zone CB in the NFL. He does not seem like a good fit for this defense, and I won’t be surprised if he ends up not making the roster.
  • Before compiling the data, I would have guessed that Jaylon Johnson was better in man than zone, but this doesn’t reflect that. If anything, Johnson fared a little better in zone than man last year, though some of that might be simply because the zone stats remove the matchup difficulty of manning up on the other teams’ best WR and level the playing field amongst CB assignments. Either way, Johnson still looks like roughly an average CB. 53 is the exact middle of the 106-man field, and Johnson slots in at 52nd and 51st, respectively, in yards/target and yards/coverage snap when in zone.

Slot Coverage

Finally, I want to take a quick look at players who covered the slot last year. I limited this to a sample of 100+ slot coverage snaps, since that gave a reasonable sample size of 74 players (2.3/team). Cutting at 250 snaps would have limited to only 21, since many teams have players cover the slot only part-time in addition to either playing safety or outside CB.

The Bears have two returning players who fit these criteria in Duke Shelley and Eddie Jackson, and recent signing Tavon Young fits the bill as well. Their performances in the slot for many of the same metrics we’ve been looking at, along with their rank relative to 74 peers, are listed below. Once again, values in the top 25% are highlighted in green, while those in the bottom 25% are highlighted in red.

A few thoughts:

  • Unfortunately, PFF doesn’t split this data by man vs. zone, or provide some of the statistics I had above (missed tackles, target depth, penalties), but there is still a good amount of information here.
  • Overall, Duke Shelley was bad, as you would have expected from the previous tables we’ve looked at. The catch % feels a bit more natural here, because everybody is seeing shorter throws. Even relative to slot peers, Shelley does a good job of keeping completed passes short but a horrible job of allowing yards after the catch, which made him one of the least effective slot defenders overall. This was the same story we saw when comparing him to all CBs.
  • Tavon Young has much of the same pattern as Shelley, but he gets targeted less frequently and is a little bit better at preventing yards after the catch. Though there’s no man/zone split here, we know from the man/zone table above that his yards after the catch difference is substantial in man coverage but disappears in zone.
  • Eddie Jackson really stands out here as a quality slot defender. He played 116 of his 429 coverage snaps (27%) in the slot last year, which was in line with his values from 2020 (137 snaps) and 2019 (134 snaps). I’ll be curious to see if the new regime continues utilizing him in that way; the most common safety defending the slot averaged 56 slot coverage snaps/year in Eberflus’ 4 years in Indianapolis, with a high of only 73.

Takeaways

Let’s wrap this up by taking a look at the overall cornerback picture:

  • Jaylon Johnson is a good – but decidedly not great – cornerback. He is still young and has the potential to grow into a great CB, but he has not yet shown that level of play on a consistent basis in the NFL. Still, Johnson is somebody the Bears should feel good about as one of their starting outside cornerbacks.
  • The likely starter opposite Johnson is 2nd round pick Kyler Gordon. Gordon comes highly regarded, but he will also be a rookie, and rookie cornerbacks usually struggle as they adjust to the NFL.
    • Gordon’s main competition will be Kindle Vildor, who is acceptable in zone coverage but atrocious in man. This should make him a solid fit as a reserve cornerback in this zone-heavy scheme.
  • In the slot, both Duke Shelley and Tavon Young are more effective in man coverage than zone, as both struggle tremendously with limiting yards after the catch in zone. This is why 2nd year man Thomas Graham seems like the favorite to win the starting nickelback job as of now, though Young’s elite man coverage skills should make him a valuable backup or rotational player, if he can stay healthy.
    • Eddie Jackson has shown the ability to be a quality slot defender as well, though it’s unclear if a new coaching staff will continue using him in that role.

Add it all up, and it’s hard to predict just how good Chicago’s CB group as a whole will be this year. Two of the three starting spots are pretty big unknowns, with a rookie the likely CB2 and a second year player who barely played as the starting nickelback. The potential is there for this to be a really good unit in the future, but there are almost certainly going to be some growing pains in 2022. Still, Vildor and Young as backups gives the Bears quality depth for the first time in forever, and a unit where four of the top five CBs will be in their first three NFL seasons makes this a young, deep, and talented group, even if it might have some rough patches this year.

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