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Can Justin Fields Upgrade Chicago’s QB Performance in 2021?

| May 17th, 2021

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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Does Andy Dalton Upgrade Chicago’s QB Room?

| May 11th, 2021

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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Bears at the Mini-Bye Volume I: Offense

| October 13th, 2020

We’re five weeks in to a wild season in which we’ve already seen the Bears make a quarterback change and post three comeback wins from 13 or more points down. Since they’re on a mini-bye following their Thursday night victory over Tampa Bay, now is a good time to take a step back and see what we’ve learned so far.

Obligatory warnings:

  • These are still small sample sizes, especially given that each QB basically played 2.5 games. So think of any lessons learned here more as observations that are worth monitoring going forward than hard and fast conclusions.
  • Statistics for Bears are updated through 5 games, but all other teams only have 4 at the time of this writing, so NFL ranks may have changed a bit by the time this is published.

I have a lot I want to get to, so let’s dive right in.


Better Lucky Than Good

The Bears may be 4-1, but I don’t think anybody would argue they have played well so far this year (including Matt Nagy). As you can see from the pie chart below, which shows the % of offensive snaps the Bears have taken in a variety of score situations, they have actually spent the majority of the season trailing.

They’ve taken 2/3 of their offensive snaps while trailing (33% by 2 or more scores) and only 19% with a lead. To somehow go from that to 4 wins in 5 games is remarkable, but it should not be expected to continue going forward. The Bears need to play better if they want to keep winning games. The good news is that they started to look better in week 5; the defense in the 2nd half looked the best it had since week 4 of the 2019 season, and the offense was something approaching competent for the last 40 or so minutes of the game.


QB Comparison

The Bears switched from Mitchell Trubisky to Nick Foles in the 2nd half of week 3, which means both QBs have actually played a similar amount of snaps so far this year (Foles is at 168, Trubisky 169). Let’s see how each performed. The table below shows stats for each passer, as well as the average for the entire NFL this year, broken up into deep and short throws (anything that travels 15+ yards in the air past the line of scrimmage is considered deep). YPA = yards per attempt.

A few thoughts:

  • Keep in mind that Nick Foles has played 2 of the best defenses in the NFL the last 2 weeks, while Trubisky played all of his snaps against 3 of the worst defenses in the league. Still, it’s hard to argue Foles has been better so far, at least on a statistical basis. He needs to play better going forward.

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Trubisky Will Start. So What Do the Bears Need From Him?

| September 6th, 2020

Friday night, news leaked that Mitchell Trubisky would be the Bears’ week 1 starting QB. While this is a decision that greatly surprises me, I want to explore what the Bears need from Trubisky in order to make it work.

This immediately led me to look for what he has done differently when he has been the most successful in his Bears career. There was actually a stretch in 2018 when he performed pretty well, starting with his breakout game against Tampa Bay in week 4 and continuing until he hurt his shoulder against the Vikings in week 11. In that 7 game stretch, Trubisky was 138 of 217 for 18 TD, 6 INT, and a 107.3 passer rating. Not every game in there was good – he had 3 games with a passer rating below 80 – but overall it was easily the most impressive stretch of his career, as you can see below (note: I’m ignoring his rookie season in 2017 and focusing solely on what he has done in this offense the last 2 years).

Three things stand out to me here:

  1. He moved the ball efficiently. Look at that yards/attempt; it’s beautiful. For context, the average NFL pass gained 6.7 yards in 2019. Trubisky was well above that for one magical seven game stretch, but has been below it for the rest of his career. And this isn’t just a one-game outlier; Trubisky was above 10 yards/attempt in three of the 7 games, and only below 6.5 in one of them. For a little more context, 8.7 yards/attempt would have ranked 2nd in the NFL last year, while Trubisky’s 6.1 yards/attempt was last in the NFL among qualified quarterbacks.
  2. He threw touchdowns. 4.5% of all passes thrown in the NFL in 2019 went for touchdowns. In that seven game stretch, Trubisky was nearly double that. Even if you remove the Tampa Bay game as an outlier, he’s still at 6.3% for the other 6 games, which is well above league average. For the rest of his career, he has struggled mightily to throw touchdowns.
  3. His legs were a weapon. This has more to do with running efficiency than volume, though you can see he also ran more often when he was at his best. From weeks 4-11 of 2018, Trubisky averaged over 8 yards/carry, while he was around 4 yards/carry in the other samples.

Those are the differences. Trubisky didn’t throw it more or less often than in other times, he didn’t complete more passes, and he didn’t avoid interceptions. He just gained more yards, threw more touchdowns, and ran it more effectively.

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Nick Foles Will Be the Starting Quarterback

| June 1st, 2020


For the Bears, there is no more important issue looming than which man will be under center receive the shotgun snap when the Bears take the field against Detroit in Week One. Today I want to dig into the stats to see what we can learn about Foles vs. Trubisky, as well as what to expect from whoever wins that derby compared to other QBs around the NFL.

The table below shows basic efficiency statistics for Trubisky and Foles in the Reid offense (so Trubisky in 2018-19 in Chicago and Foles in 2016 in KC and 17-18 in Philadelphia), plus the other three notable recent Reid QBs (Smith 13-17, Mahomes 18-19, Wentz 16-19). I’ll note I included playoff stats for everybody because otherwise Foles’ sample size is just so small (less than 350 with just regular season, just over 500 with playoffs included). I also included the NFL average for 2018-19 as a frame of reference for what’s roughly normal around the league. I split up the data into short and long passes (targeted more than 15 yards past the line of scrimmage) using Pro Football Reference’s game play finder.

That’s a lot of information to digest, so let’s look at short and deep passes separately.


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What are the Bears Getting in Nick Foles?

| March 19th, 2020

The Bears traded a 4th round pick for Nick Foles, and the Bears officially have their new quarterback.

On the surface it might seem puzzling to trade for a 31 year-old quarterback who hasn’t thrown 200 passes in a season since 2015, but one of the big draws for Foles was his familiarity in Matt Nagy’s offense. He played for Nagy in Kansas City in 2016 and in the same scheme in Philadelphia under Doug Pederson in 2017-18. This could be especially important in this offseason, when team activities might not happen before training camp due to Covid-19.

Let’s take a look at some advanced statistics to see how Foles has performed in this offense. In my view, advanced statistics tell us as much about a quarterback’s approach as they do his efficiency. From them, you can see if he favors holding the ball to make a play or getting it out quickly to avoid taking a sack, pushing it deep or throwing it underneath, and making safe passes or taking chances into coverage.

The table below shows a battery of advanced statistics for Foles from 2016-18. For comparison, I included Mitchell Trubisky’s stats from his time under Nagy, and also Alex Smith’s from his time in this offense in Kansas City (the Next Gen Stats database only goes back to 2016, so I couldn’t make his sample any larger). I’ll note that Foles’ stats include playoff games to make the sample a bit bigger; even with that, it’s barely over 500 passes, and about 1/3 of that comes from the playoffs. I color-coordinated columns into general categories: basic efficienty stats (gray), throwing distance (blue), throwing time (tan), and taking chances (green). All data comes from Next Gen Stats except deep passes, which are from Pro Football Reference.

A few thoughts:

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The Non-Trubisky Offensive Issue: Personnel Usage Remains a Problem

| February 10th, 2020

It’s no secret that I’ve blamed quarterback Mitchell Trubisky for the lion’s share of Chicago’s offensive shortcomings in 2019, while pointing out contributing factors elsewhere: tight end, run blocking, Tarik Cohen…etc. But I truly believe that a competent quarterback would have put the Bears in the playoffs in 2019.

However, it’s important not to get too fixated on one issue and ignore other problems. So today I want to look at offensive issues from 2019 that have absolutely nothing to do with Mitchell Trubisky, but instead are due to what I believe to be poor coaching decisions regarding personnel usage.


Personnel Predictability

How predictable was Chicago’s offense when several of their key players were on or off the field?

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 almost never leave the field (Allen Robinson played over 93% of offensive snaps in 2019) because their “off field” splits would be too small to be worth considering.
  • On the low end, it excludes situational players who often only come in for situations where a run or pass is expected (ie the 4th WR in a 4 WR set for 3rd and long, or the 2nd TE in a short-yardage set).

Instead, I want to look at how the Bears deployed their key skill position players as they rotated through in a game.

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

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Least Explosive Team in the NFL, or the Story of the 2019 Chicago Bears

| February 4th, 2020

I’ve been working my way through the Bears’ 2019 performance to see what changed from 2018 that caused them to slip from 12-4 to 8-8. Today, I want to look at explosive plays, which I found last season have a strong correlation to overall offensive performance.

There are a variety of definitions for explosive plays depending on who you ask, so I want to clarify I’m using parameters laid out by ESPN NFL Matchup, which counts any run that gains 15+ yards or pass that gains 20+ yards as explosive. Let’s start with a preliminary look at how the Bears did in 2019 relative to the rest of the NFL. All data is from Pro Football Reference, with explosive play information coming from the Game Play Finder. Pass percentages were calculated including sacks and pass attempts as pass plays.



That’s ugly.

If you want to compare to 2018, the Bears slipped across the board. They had 71 explosive plays in 2018, with explosive rates of 7% overall, 5.3% on runs, and 8.4% on passes. All of those numbers in 2018 were slightly below average, ranging from 18th to 21st in the league, while they are all bottom 2 in 2019.

So what happened to cause such a slump? Like I’ve done when evaluating both the running and passing games, I want to break down what it looks like for individual Bears players and/or position groups from season to season. That information is shown in the table below, with all cells formatted by 2018 / 2019 data. (I’ll note the pass rates are a bit higher for pass catchers than QBs because they are only out of targets and exclude sacks and throwaways.)


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What Changed in the Passing Game: Volume III

| January 24th, 2020

Today I want to look back at two areas of concern I noted for Trubisky last off-season: deep passes and performance against good defenses.


Deep Passes

Last year, I noted that Trubisky was really good at short passes (15 yards or less past the line of scrimmage) and really bad throwing the ball deep. I also found that short passing performance tends to be less variable year over year than deep passing, which gave us a reason to be optimistic about Trubisky heading into 2019.

Let’s see how that theory played out in 2019.

A few thoughts:

  • So much for short stuff being consistent. Trubisky’s completion percentage, yards/attempt, yards/completion, and touchdown rate all plummeted from 2018 to 2019.
  • Some of the completion percentage can be accounted for by drops (as I have previously addressed), but not nearly all of it on the short stuff. Despite throwing shorter passes in the short stuff, Trubisky completed fewer of them. The end result was an extremely inefficient short passing game.

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What Changed in the Passing Game: Volume II

| January 23rd, 2020

Yesterday, it was discovered that the pass blocking and drops by pass catchers went from really good to about average.

The hypothesis, then, is that the quarterback was largely responsible for the Bears having one of the worst passing games – and thus worst offenses – in the NFL. So today I want to look at Mitchell Trubisky’s performance more closely to see what it can tell us.

On the surface, Trubisky certainly was awful in 2019. He completed 63.2% of his passes (18th in the NFL), averaged 6.1 yards/attempt (last), and posted a passer rating of 83.0 (28th). This was a big step back from 2019, when he was near average in all of those marks (66.6% completion, 14th; 7.4 yards/attempt, 18th; 95.4 rating, 16th).

Evaluating a quarterback’s play statistically can be tricky, because his stats depend both on his offensive line’s ability to block for him and his RBs/WRs/TEs’ ability to catch his passes, both of which are outside of his control. That’s why I started by looking at the offensive line and drops, both of which were worse in 2019 than 2018 but not nearly bad enough to explain bottom 5 production from the quarterback.

It’s also worth noting that Chase Daniel’s production barely changed between seasons. In 2018, he completed 70% of his passes, averaged 6.8 yards/attempt, threw 3 TD and 2 INT, and posted a 90.6 passer rating. In 2019, he completed 70% of his passes, averaged 6.8 yards/attempt, threw 3 TD and 2 INT, and posted a 91.6 passer rating. To be fair, it’s a small sample size – he played 2 games and threw around 70 passes each year – but still, this is at least anecdotal evidence to support the notion that the offense as a whole didn’t change all that drastically.


Advanced Stats

With that said, let’s look more closely at Trubisky’s performance to see if we can hone in on what changed, besides worse pocket presence and less running impact, which were touched on in previous articles. This is going to focus on passing. We’ll start by looking at a smattering of advanced statistics, which come from a combination of Next Gen Stats and Pro Football Reference.

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