Let’s continue our quick tour of Chicago’s defense by honing in on pass coverage.

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At a surface glance, Chicago’s pass defense was just about the definition of average in 2020. They gave up 64% completion (14th in the NFL), 7.2 yards/attempt (16th), 28 touchdowns (16th),  had10 interceptions (23rd), and allowed a passer rating against of 94.9 (20th). They were 21st in Pro Football Reference’s Adjusted Net Yards/Attempt, which accounts for sacks, touchdowns, interceptions, and yards, and 13th in Football Outsider’s pass DVOA rankings, which is intended to be a one-stop measure of pass defense overall.

A closer look at advanced statistics from Next Gen Stats shows how QBs playing against the Bears played relative to the rest of their games and the NFL average.

A few thoughts:

• Opposing QBs generally didn’t see any change against the Bears in terms of how long they held the ball before throwing it. This means that Chicago’s pass rush wasn’t forcing them to get rid of the ball quickly, but also didn’t let them hang onto it forever. Again: average.
• In terms of where QBs threw the ball against Chicago, opposing QBs typically threw it slightly deeper against the Bears than other opponents, though the difference is pretty subtle (for context, individual QBs ranged from 5 to 11 yards for average pass depth). That small difference was completely eliminated when looking at average completion depth.
• Opposing QBs also threw into tight coverage (aggressive throws) slightly more than normal against the Bears, though again that’s not a huge difference. For a little context, individual QBs on the year ranged from averaging 11% to 22% on aggressive throws.

Now that we’ve firmly established the overall pass defense was around average, let’s look at how individual players fared in coverage last year to see where Chicago might have strong and weak spots. We’ll go position by position, using advanced data from Pro Football Reference.

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Continuing our tour of advanced statistics about Chicago’s 2020 defense, today I want to take a look at missed tackles.

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The Bears excelled in the missed tackle area last year, finishing with only 89, the 6th lowest mark in the NFL. To go more in-depth, let’s hone in on how individual players and units contributed to that, building on work I did last offseason. The setup here is fairly simple:

• Split players into positions (DL, LB, and DB).
• Compare their missed tackle rates to how everybody else around the NFL fares at their position.

You can see the full data here, but generally the positional medians for missed tackle rates are 10.8% for DB, 9.5% for LB, and 8.5% for DL. With that in mind, let’s look at how Chicago’s defense did last year.

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Defensive Backs

The table below shows all Chicago defensive backs in 2020, as well as how they did overall as a unit. Players with 20 or more tackle attempts were ranked based on how they fared relative to all NFL DBs.

A few thoughts:

• Eddie Jackson continued to struggle with missed tackles for the 3rd year in a row. It’s not his strength, but that’s fine if he continues to excel in coverage, which is far more valuable (spoiler alert for upcoming article: he did not excel in coverage in 2020).
• Tashaun Gipson struggled with missed tackles in both 2018 and 2019, but was excellent here in 2020. The Bears will need him to continue to excel in that area given the tackling question marks around him.
• Kyle Fuller and Jaylon Johnson were both awful with missed tackles in 2020. That continued a long-time pattern for Fuller, but was a bit of a surprise for Johnson, who rarely missed tackles in college. However, I should note that 6 of his 9 missed tackles came in the last 4 weeks as he played through a shoulder injury before it shut him down for the year. In his first 9 games, he had a missed tackle rate of only 10%, which is around league average.

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Over the next few days, I want to look at advanced defensive statistics from Pro Football Reference to better examine some of Chicago’s individual defenders as we prepare for the 2021 season. Today will focus on pass rush, while upcoming articles will examine missed tackles and pass coverage.

On the surface, Chicago’s pass rush was not terribly impressive last year. The Bears finished with 35 sacks (17th in the NFL) and 137 pressures (23rd). They pressured QBs on only 22.4% of dropbacks, which ranked 21st of 32 NFL teams. I’ll note here that pressures can be a somewhat subjective stat, and thus they differ a bit from source to source. Pro Football Focus, for instance, had the Bears as the 4th best pass rush in the NFL.

I don’t have access to PFF’s data, however, so I’m going forward with Pro Football Reference numbers. I specifically want to hone in on pressures today, because those tend to be a more reliable measure of pass rush effectiveness than sacks. Last offseason, I found that, on average, NFL players get about 3.8 pressures per sack. This allows you to get a feel for expected sacks (pressures/3.8), which you can then compare to the actual sacks to see which players got lucky (more sacks than expected) or unlucky (less sacks than expected). I found there is no carryover from one season to the next in this stat, so it gives us an idea of what players we might expect to bounce back the upcoming season.

When looking at league-wide data for 2020, I noticed that total sacks seemed lower. The pressure numbers were about the same (105 players had 15+ pressures in 2020 compared to 107/year in 2018-19, 36 players had 30+ pressures compared to 32 per year in 2018-19) but I found there were 4.3 pressures per sack in 2020. My hypothesis is that the NFL calling fewer holding penalties led to more pressures where the pass rusher couldn’t finish the play. Either way, I used the 4.3 pressures/sack number to get the expected sacks for Bears players in 2020, and you can see how they did compared to their actual sacks below. Players in green outperformed their expected sack total by at least 1 sack, while those in red underperformed by at least 1 sack.

A few thoughts:

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Like I’ve done the last few seasons, I want to explore how the Bears deployed their skill position players on offense in 2020 to see if there are any trends or tells for which opposing defensive coordinators can look. These are tendencies Chicago’s coaches should be aware of and look to rectify in the future.

The table below shows changes in run percentage when skill position guys who played between 35-65% of the snaps were in the game vs. on the sideline.

• On the high end, that excludes players who played more than 75% of snaps, because their “off-field” splits would be too small to consider. That was only Allen Robinson in 2020.
• On the low end, that excludes players who played less than 25% of snaps, because they are often mainly in the game in specific situations, where a run or pass may be expected (i.e. the 4th WR in a 4 WR set for 3rd and long, or the 2nd TE in a short-yardage set). This excluded Demetrius Harris, Cordarrelle Patterson, and a host of other role players who played a few offensive snaps.

(Note: This data is pulled from the NFL Game Statistics and Information System, which includes sacks and QB scrambles as passing plays.)

A few thoughts:

• David Montgomery had pretty even splits when he was on and off the field. Therefore I won’t look at him any further when I split the sample into different personnel packages below.
• This is a change from 2019, when Montgomery’s presence on the field made a run much more likely, and is almost certainly due to Tarik Cohen’s injury. In Cohen’s limited 76 plays before getting hurt, the Bears only ran it 29% of the time. He clearly had the passing downs role, and Montgomery absorbed that when Cohen got hurt.
• Everybody else has fairly significant changes in how frequently the offense runs when they are on the field vs. off of it, which warrants further exploration.

Different Personnel Groupings

I was curious how much the personnel groupings might influence these splits, so I looked at how frequently the Bears run the ball in different groupings. Generally, there are five skill position guys (WR, TE, RB) on the field for a given play, so I split the sample up by how many of them were wide receivers.

The more WR the Bears have on the field, the more likely they are to pass. That makes sense, but the significant difference in run frequency here means we’re going to have to look at each of these groups individually to see how players really impact the run/pass ratio when they are on the field.

3+ Wide Receivers

Let’s start with plays featuring 3 or more WRs, which means there are 2 total TE + RB. The most common setup here was 11 personnel, which features 1 RB, 1 TE, and 3 WR.

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The Bears traded up in the second round to select Teven Jenkins and then promptly cut Charles Leno, paving the way for Jenkins to take over as the starting left tackle on day one. Bears fans have high expectations for Jenkins, helped along by Ryan Pace saying he gave Jenkins a first-round grade.

With that context in mind, I thought it might be helpful to look at recent history of tackles drafted in the second round. This can give us an idea of what to expect from Jenkins, and see what rough odds are for him becoming a quality starter vs. being a bust. I looked at all draft picks from 2011-20 to give a 10-year sample featuring 26 players. Full data can be seen here.

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Most Start as Rookies

18 of the 26 tackles (a very nice 69%) drafted in the second round started as rookies. Starter can be a bit difficult to define here due to injury and mid-season depth chart changes, so I considered them starters if they played more than half of their offense’s snaps and started in more than half of the games they appeared in, according to Pro Football Reference.

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They Stay on the Field

All 18 of the players who started as rookies spent at least three years as a starter, or have not yet played three years in the NFL but are projected to continue starting in 2021.

11 of the 13 with four or more years of experience spent at least four seasons starting.

Of the 12 rookie starters drafted in 2015 or earlier (so at least 6 NFL seasons by now), nine of them have been a starter for six or more years, with more than half (7) being a starter for at least 8 years (or 6+ years and projected to continue starting in 2021).

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A whole lot of attention has been paid to Chicago’s offense and defense this offseason, but there hasn’t been much focus on the unit that will see the largest turnover from 2020: special teams.

Bears special teams were quietly very good last year; they ranked 8th in total DVOA according to Football Outsiders, and were among the 10 best NFL teams in field goals, kickoff coverage, kickoff returns, and punt returns.

This was not a usual result for Chicago, as 2020 was the first year they were ranked in the top 10 for ST DVOA since 2012. To put that in perspective, in 2012 Lovie Smith was still the head coach, Dave Toub the ST coordinator, Devin Hester the return man, Robbie Gould the kicker, and Patrick Mannelly the long snapper. Those were the days.

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General Changeover

So how did Chicago celebrate their 2020 special teams success? By changing over much of the unit. The specialists – K Cairo Santos, P Pat O’Donnell, and LS Patrick Scales – all return, but many of their core ST players will not. Just look at the table below, which shows all 12 Bears who played at least 30% of the ST snaps last year.

The players highlighted in red are no longer with the Bears, and make up nearly half the list (5 of 12). Two more core special teamers – RB Ryan Nall and OLB James Vaughters – saw additions made to their position this offseason that leave them with an uphill climb to make the roster again. If those two are not able to stick, then 7 of the 12 players on this list will be gone. That leaves a whole lot of special teams snaps that will need to be filled.

The good news is that the Bears have emphasized bringing in players with ST experience this offseason. The table below shows new Bears who were core ST performers at their last stop. An * indicates the ST experience was in college.

You can see fairly logical replacements for the players who are leaving from above.

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Today, I want to take a closer look at Justin Fields’ advanced statistics in college to see what they can tell us about his playing style, comparable quarterbacks, and forecast to the NFL.

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Pass Location and Accuracy

To start out, let’s take a look at where Fields throws the ball and how accurate he is to different areas of the field. This data is pulled from Derrik Klassen, who has charted 28 draft-eligible QBs across 2019, 2020, and 2021. The table below shows how frequently and effectively Fields threw the ball short (5 yards or less), medium (6 to 15 yards), and deep (16 or more yards). It also compares each value to the average of the 28 QBs.

A few thoughts:

• Fields is generally a very accurate passer. He’s one of the top 10 in accuracy to each range of the field, and ranks 1st among the 28 in “True Accuracy,” which is Klassen’s distance-weighted accuracy summary.
• Fields also did not throw short passes all that frequently. It’s often hard to evaluate college QB production because so much of it comes from schemed short passes that don’t require much from the QB. Fields was one of the QBs who threw short the least, which means more of his production came down the field than a typical college QB.
• Fields also didn’t throw it deep all that much, but he was really good when he did. I’ll look in more detail below at how well that translates to the NFL.
• Where Fields really stood out, both in frequency and accuracy, was the midrange game. Fields’ 80% accuracy tied with Mac Jones, and nobody else in the sample was above 75%.

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Translation to NFL

So Fields is really accurate and likes to target the middle range of the field often. How well do those traits translate to the NFL?

I’m actually going to focus on two slightly different traits here, because they’re ones where I have easy access to the data (using Pro Football Reference’s Game Play Finder). That lets us view deep passes, which travel 15+ yards past the line of scrimmage, separate from short passes, which travel less than 15 yards.

When it comes to deep passes, Fields threw them at a slightly lower than average frequency in college, but was one of the most accurate passers in the last 3 drafts. How well do those traits translate to the NFL?

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Recently, I looked at Andy Dalton and found that he is not likely going to improve on the production the Bears got from their QBs in 2020. That means any improvement in the QB room likely has to come from rookie Justin Fields.

This is a more difficult projection to make because Fields doesn’t have years of NFL production to look at for an apples-to-apples comparison like I did with Dalton. Instead, I’m going to look at all rookies drafted in the last 10 years (2011-20 drafts) who attempted at least 300 passes in their rookie NFL season, with the idea being they played the majority of the year. This gives a sample size of 29 QBs; how many of them performed better than Chicago’s QBs in 2020?

The Setup

To do this comparison, I’m going to look at 3 stats, which I want to briefly explain here:

• Yards per attempt + (Y/A)+. Yards per attempt is a simple enough metric, but the + indicates it is adjusted for era. Since this is comparing QBs over a 10 year sample, and league-wide yards/attempt has fluctuated year-by-year, this scales them all accordingly. 100 is a league average mark, anything higher is better and lower is worse.
• Adjusted net yards per attempt + (ANY/A+). This takes yards/attempt and factors in touchdowns, interceptions, and sacks, and then scales according to league averages that year. A full explanation of the formula for adjusted net yards/attempt (which is from Pro Football Reference, just like Y/A+) can be seen here. The scaling is the same as Y/A+ above; 100 is average, and higher is better.
• Expected Points added (EPA/Dropback). This attempts to account for the value of each individual play by comparing expected points on the drive (based on down, distance, and field location) at the start and finish of a play. Generally speaking, higher values here indicate that QB’s team is expected to score more points over the course of the season. A more detailed explanation can be found here. EPA data is pulled from this website.

The idea here is simple enough: how many of the 29 rookie QBs in the last 10 years with 300+ pass attempts have outperformed Chicago’s QBs from 2020? I also threw Andy Dalton’s 2020 season in just as a point of reference. Full data can be viewed here. 

Results

The table below shows how the Bears did in all 3 stats in 2020, how Andy Dalton did in all 3 stats in 2020, the average for all 29 rookies in the sample, and the number of rookies who outperformed the better of the 2020 Bears/2020 Dalton in each stat.

A few thoughts:

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The Bears completely overhauled their QB room this offseason, letting Mitchell Trubisky leave, signing Andy Dalton, and trading up in the 1st round to draft Justin Fields. The goal is obvious: improve a passing attack that finished last year ranked 28th in yards/attempt, 18th in passing TD, threw the 4th most interceptions, and had the 24th passer rating among 32 NFL teams.

With that in mind, I want to look at each of the additions compared to who they replaced to see how likely it is that they actually provide the desired upgrade. I’m starting today with Andy Dalton, who the Bears have insisted is still their starter.

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Basic Stats

Let’s start with a surface-level view of Dalton’s passing stats compared to Trubisky and Nick Foles, the 2020 QBs.

Since playing time has been spotty for all of them over the last few years, due to a combination of injury and sometimes being the backup, I’m going to use cumulative 2018-20 stats for all of them to give a decent sample size (600+ pass attempts for each). I’ll include the NFL average over that time period to see how each QB stands relative to their peers.

As you can see there, a first glance makes it look like Dalton doesn’t provide much improvement over the status quo. The three QBs vary quite a bit in completion percentage, but all come up well below the NFL average in both yards per attempt and TD to INT ratio. If anything, Trubisky was the most productive QB of the three (though this is not an argument for keeping Trubisky. They are all bad NFL QBs). If you’re really curious about the 2020 Bears specifically, they completed 66% of their passes, averaged 6.4 yards/attempt, and had 1.6 TD for every INT.

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Short/Deep Split

However, we can take a closer look to see if there’s something we might be missing. Let’s split up passes into short (less than 15 yards past the line of scrimmage) and deep (15+ yards past the line of scrimmage). Here’s the same table as above, only with that split applied. Short passes are highlighted in orange, deep passes in blue.

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The 2021 NFL draft starts tomorrow, so I want to take a look at historical trends to see where the Bears can expect to find positional value at various points in the draft. This builds very closely off a study I did last year, so here’s a quick recap of the approach:

I looked at every draft from 2010-20 to see how many players at each position were drafted in the top 50 (their 2nd round pick is #52), top 85 (their 3rd round pick is #83), and top 175 (their 5th round pick is #164). I didn’t bother looking at their 1st round pick because the top of the draft is more about a small pool of individual players as options, and the heavy focus in draft media on the 1st round means most fans are already pretty familiar with those names.

• My source for this data did not differentiate between CB and S, so I combined the 2 into DB.
• They did differentiate between interior offensive line and offensive tackle, so I kept those separate.
• They had LB and DE as separate, with some edge rushers on both lists. I included all DE as edge rushers (even though some were more 3-4 DEs, not true edge rushers) and manually went through the LB list, looked up scouting reports for every player, and included anybody who was talked about as an edge rusher.

I then used The Athletic’s composite big board, which averages rankings from a number of different draft sources, to compare to historical trends. I focused especially on positions which I identified as needs for the Bears. The idea here is that positions with more players than usual ranked in a given range are more likely to have somebody highly rated slip through the cracks, while positions with fewer players than usual ranked in a given range are more likely to have somebody reach for them to fill a need.

Round Two (Top 50)

Here is the data for players drafted in the top 50.

• Because every draft is different, I provided a range from the least to most players at that position drafted in the top 50 picks since 2010, as well as an average.
• The last column shows how many players from that position are ranked in the top 50 right now according to the composite big board linked above.
• Positions that are particularly good or bad are highlighted in colors (red for historically low, orange for near the low end of the range, light green for near the top end of the range, and green for historically good).

A few thoughts:

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