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Do Justin Fields’ Rookie Fumbles Portend a Fumbler? Data Says It’s Unlikely.

| May 17th, 2022


Despite only starting 10 of 17 games last year, Justin Fields fumbled the ball 12 times, which was the 4th highest mark in the NFL. That’s a real problem. Since fumble recovery is random, meaning you will lose roughly half of your fumbles, that’s an additional turnover around once every two games. Given the strong relationship between turnovers and game outcome, this is a recipe for losing a whole lot of games.

But is this a problem that is likely to continue for Fields? Let’s see what history might be able to tell us.

Fumbling Rookies.

It is surprisingly common for rookie QBs to fumble the ball. A lot. Since 2001, there have been 24 instances of a rookie QB fumbling the ball ten or more times. Looking at the rookies who have played the most, there are 61 rookie QBs in that time span with at least 250 pass attempts, and 22 of them (more than 1/3) had at least ten fumbles.

So, in that regard, Fields is in good company. While many of the QBs on that list went on to bust status, there were plenty of successful QBs as well, including Lamar Jackson, Andrew Luck, Derek Carr, Alex Smith, and Carson Wentz as long-time starters.

This led to a logical follow-up question: do QBs who fumble a bunch as rookies improve after that? In order to explore this, I tracked fumble rate through two methods:

  • Plays per fumble, which includes all pass attempts, sacks, and rushes. This is a measure of how often a QB fumbles compared to how often the ball is in his hands.
  • Hits per fumble, which includes all sacks and rushes as plays in which the QB got hit. This is a measure of how often a QB fumbles when exposed to contact with the ball in his hands.

I should note that this list only includes QBs who had 1000+ career pass attempts total, such that there was a large enough post-rookie sample size to gather meaningful data. This gave a sample size of 17, which includes over 8,000 rookie plays and 40,000 non-rookie plays.

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If Sustained Success is Entirely Dependent on QB Play, Ryan Poles’ Process for 2022 is Questionable

| May 12th, 2022

In his opening press conference as the general manager of the Chicago Bears, Ryan Poles boldly proclaimed his goal to “sustain success over a long period of time.” This is a fairly standard thing to say for a new general manager, because it’s what everybody in the NFL is trying to accomplish. But today I want to evaluate Poles’ approach to his first offseason in charge of a team with that goal in mind.


How to Achieve Sustained Success

Fact 1: Offense is far more stable than defense year over year. To put it another way, defensive success is not sustainable – a fact Bears fans should be intimately familiar with after the last five years. Thus, the main factor to drive sustained team success is going to be sustained offensive success.

Fact 2: Good offensive play is driven by good QB play. This makes perfect sense, and I think we all knew it, but it’s good to have proof to back it up.

Conclusion: The best path to sustained success is a good QB. A brief look at recent NFL history supports that notion:

If you consider making the playoffs to mean success, there have been 18 instances in the last ten years where teams made the playoffs at least three times in a four-year span. Ten of those involved a solid or better QB on a rookie deal as the primary starter, while six more featured future HOF QBs on veteran contracts.

Only two of 18, then, involved solid-but-unspectacular QBs who weren’t on rookie deals. Those were Tennessee with Ryan Tannehill and Kansas City with Alex Smith. So, it is possible to sustain success without a really good QB or cheap solid QB, but it’s a much less likely path.

It’s also worth noting that both of those two found very little success in the playoffs. Only three of nine playoff seasons featured a playoff win, and only one reached a conference championship game. So, if your definition of sustained success involves more than bouncing out of the playoffs early on, those don’t really meet it.

If you want to get more selective and look at playoff success as an indicator of success, this list gets even more QB-dependent.

  • 28 of 40 teams in the conference championship game featured a starting QB with at least one All Pro or MVP in their career, and that doesn’t include Andrew Luck (retired early before achieving either of those) or Joe Burrow (only two NFL seasons so far, seems headed in that direction).
  • Only eight NFL QBs have started at least two conference championship games in the last decade, and six of them have made an All Pro or won MVP.

Again, this doesn’t mean getting a really good QB is the only path to sustained success (see SF with Alex Smith/Colin Kaepernick about a decade ago, or SF with Jimmy Garoppolo the last several years). It’s just the most likely path to sustained success.

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Using Historical Trends to Guide Chicago’s Draft Approach

| April 28th, 2022


Let’s 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 work I’ve done each of the last two years, and here’s a quick recap of the approach:

  • I looked at the last 15 drafts (2007-21) to see how many players at each position were drafted in the top 50 (their 2nd round picks are #39 and 48), top 70 (their 3rd round pick is #71), and top 150 (their next picks are #148 and #150). I didn’t look at the 1st round because the Bears don’t have a 1st round pick this year.
    • My source for this data did not differentiate between CB and S, so I combined those into DB.
    • They did differentiate between interior offensive line and offensive tackle, so I kept those separate.
  • 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 believe are the primary 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.

This is my third year applying this approach to the draft, and I was a bit hesitant about it at first, because it seems risky to rely on draft rankings from people who don’t work in the NFL. It’s quite possible that people in the NFL view these players entirely differently. However, I think the track record has been pretty solid over the last two years. For instance:

  • In 2020, I found the Bears should look to grab a defensive back early, because the depth on day three was not very good, and they landed Jaylon Johnson in round two. I also found the value at WR should be good throughout the draft, so the Bears could add there at any point, and they found Darnell Mooney in round five.
  • In 2021, I found the QB class was loaded at the top but not deep, so the Bears should look to take a QB early. At the same time, I found the OT class was historically deep, so they should look to draft one early and another late. They ended up with Justin Fields, Teven Jenkins, and Larry Borom all contributing as rookies.
  • Of course, it hasn’t all been great. In 2020 I said the Bears would not find value at TE in round 2, and they landed Cole Kmet, who has at least been a capable player (even if I don’t think he’s particularly great).

This is definitely an inexact science, and we don’t want to put too much stock in it, but I think it’s a useful exercise to see what positions might have more good players than usual, and thus possibly value for the Bears.


Round 2 (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 2007, 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:

  • It’s a good year for the Bears to need a WR, especially at the top of their draft. There are nine WRs ranked in the top 50 on the composite big board, there have been eight or fewer WRs taken in the top 50 13 times in the last 15 drafts. If history holds here, the Bears should have some solid value options at WR with either of their second round picks.
  • There also seems to be pretty solid value at defensive back, where 12 players are ranked in the top 50 and 13 of the last 15 drafts have seen 11 or fewer DBs selected in that range. The Bears could use starters at outside CB, nickel CB, and safety, so they may look to fill one of those spots in the second round.
  • The rest of the Bears’ biggest need positions are right around their historical averages, meaning there may or may not be value present for the Bears, depending on how the draft falls.

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My Draft Crush: Memphis WR Calvin Austin III

| April 26th, 2022


It’s no secret that the Bears need a WR, but I would take it even further; they should enter the weekend with the goal of drafting two wideouts they think can contribute right away.

One of those has to be a bigger-bodied WR, which they are sorely missing right now, but my draft crush does not fit that bill.

In fact, Memphis WR Calvin Austin III comes in at the other end of the spectrum for WRs. He stands only 5’7″ and weighed in at the Combine at only 170 pounds. If you’re going to be that small, you need to be an athletic freak to make it at the NFL level, and Austin certainly fits the bill.



This is Austin’s Relative Athletic Score, or RAS, based on his Combine performance. RAS scales everything against historical players at your position from 0 (worst) to 10 (best). As I’ve already said, Austin is tiny, but he scores in the top 8% amongst WRs in literally every athletic testing metric (credit to Kent Lee Platte for RAS data), placing him in the top 6% overall in total athletic ability.

That athleticism certainly shows up when you watch Austin play. He’s both fast and quick, and his change of direction abilities are noticeable in tight spaces. This speed and acceleration lets Austin excel after the catch, as he had the 5th highest yards after the catch/catch mark of all WRs in the 2022 draft.

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Can Cole Kmet Be More Than a “Useful” Player?

| April 22nd, 2022

Chicago Bears TE Cole Kmet saw his production jump across the board in his 2021 sophomore campaign, as his targets, receptions, and receiving yards all more than doubled from his rookie year. This left him ranking among the top 20 NFL TEs in the main three receiving categories, as you can see in the table below.

Of course, those are all volume stats, and high volume does not necessarily mean that you are a top player. Chicago’s receiving options were extremely limited in 2021, and the former coaching staff had a vested interest in getting Kmet the ball to justify their second-round investment in him, so of course he saw a lot of balls thrown his way. But how effective was he with those targets?

In order to dig into that question, I’m going to take a closer look at Kmet’s underlying metrics to see how well he performed. This will be very similar to what I recently did with Darnell Mooney, the only other returning pass catcher on the Bears.


Man vs. Zone

Let’s start by looking at how Kmet did against man and zone coverages compared to his peers. I split the overall TE group based on how many targets players earned, and the sample broke down like this:

  • 50+ targets: 25 TEs fell in this group. With 32 NFL teams, this is more or less the starting TEs.
  • 20-49 targets: 33 TEs fell in this range, meaning these are generally the second TEs on a team.
  • Less than 20 targets: 64 players fit in here, so these are the depth TE on a team.

The table below shows how TEs in those groupings performed in a variety of metrics against both man (orange) and zone (blue) coverage. All stats are from Pro Football Focus (PFF).

A few thoughts:

  • Like we did with Darnell Mooney, it’s important to take the offense into consideration when evaluating Kmet’s stats against his peers. The Bears as a team ranked in the bottom five in the majority of passing categories, so it’s not really a surprise to see some of his efficiency stats looking low. For example, the Bears were about 4% lower than the NFL average in completion % (catch % here) and 0.4 yards below the NFL average in yards/attempt (yards/target here).
  • Given that context, Kmet served as a capable weapon against zone coverage. His catch percentage and yards/target mark are fairly solid, if unspectacular, though it’s worth noting his poor YAC (yards after catch) performance. Time will tell if that’s a scheme issue from last year (Andy Dalton and Justin Fields ranked 21st and 31st, respectively, in YAC/completion of the 33 QBs with 200+ passing attempts in 2021) or a Kmet issue, but it’s worth noting Mooney did not have the same YAC issues. Kmet’s average catch against zone is also a bit shorter down the field than most starting TEs, which is notable considering how Justin Fields had one of the deepest average passes in the NFL last year.
  • Kmet’s man metrics, on the other hand, are unquestionably poor. His catch rate was just fine, but his average catch against man was very short, indicating he was only able to produce against man coverage on dump-offs underneath. This is in line with the TE2 and depth TE group, not the starters. Kmet’s YAC here was also laughably bad, indicating he was unable to consistently break tackles and turn those dump-offs into more meaningful gains.

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With Floor Established, Where is the Ceiling: A Closer Look at Darnell Mooney

| April 21st, 2022

After a promising rookie campaign, Chicago Bears WR Darnell Mooney had a breakthrough sophomore season in 2021. He posted the first 1000-yard season of his career and, as you can see in the table below, was among the top 20 WRs in the NFL in the three main receiving categories.

Of course, these are all volume stats, and high volume does not necessarily mean you are a top player. Mooney was the only not-terrible WR in Chicago last year, so he naturally saw a lot of balls thrown his way. As the only returning WR in 2022, I think it’s worth digging a bit into the advanced statistics to see how well Mooney did with those passes.


Man vs. Zone

Let’s start by looking at how Mooney did against man and zone coverages compared to his peers. I split the overall WR group based on how many targets players earned, and the samples broke down like this:

  • 100+ targets: 33 WRs fell in this group, and with 32 NFL teams, this was basically the WR1s.
  • 50-99 targets: 56 WRs are in this group, making it the WR 2 + 3 for each team. These are generally starters, but not the top targets.
  • 30-49 targets: 28 WRs are in this group, making it roughly a teams’ WR4. These are the top backups.
  • Less than 30 targets: 117 WRs (about 3.6/team) fell in this group, and these can be viewed as depth pieces.

The table below shows how WRs in those groupings performed in a variety of metrics against both man (orange) and zone (blue) coverage. All stats are from Pro Football Focus (PFF).

A few thoughts:

  • It’s important to take the offense into consideration when evaluating Mooney’s stats against his peers. The Bears as a team ranked in the bottom 5 in the majority of passing categories, so it’s not really a surprise to see some of his efficiency stats looking low. For example, the Bears were about 4% lower than the NFL average in completion % (catch % here) and 0.4 yards below the NFL average in yards/attempt (yards/target here).
  • Even given that context, Mooney’s catch percentage is still quite low against both man and zone coverage. In man, this can be explained by his deeper targets (higher air yards/target), but that’s not true in zone. Mooney’s drop rate was not an issue (4.7%, 12th best of 33 WRs with 100+ targets), so I’m inclined to chalk this up to a high rate of uncatchable passes (Justin Fields was one of the least accurate passers in the NFL last year).

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Fields in Focus Part VII: Rookie Comparison

| February 22nd, 2022

So far, this series has focused on what Fields did well and where he struggled during his rookie season. Now I want to broaden this to think a bit about what it could mean for his future. In order to accomplish that, I’m going to compare Fields’ stats in a wide variety of categories to those of every other rookie QB with at least 250 pass attempts in the last decade. All data will come from Pro Football Focus (PFF) unless otherwise noted.


Overall Comparison

Including Fields, there have been 37 QBs who attempted at least 250 passes during their rookie season over the last 10 years. The data below shows how Fields compared to the rest of the sample in a variety of wide-ranging metrics. Places where Fields ranked in the top 10 are highlighted in green, while those where he ranked in the bottom 10 are highlighted in red.

A few thoughts:

  • Overall, this matches what we saw with Fields when compared to all 2021 QBs. He holds the ball a long time, pushes it down the field, doesn’t complete a lot of passes, but is generally decent in yards/attempt, big time throws, and turnover worthy plays. He generally ranks a bit better in most areas when compared to other rookies than he did compared to all 2021 QBs, but that makes sense; most rookie QBs are bad.
  • What do these stats mean going forward? I tried to look at a few of them to see if they could project anything.
    • If you do a simple big time throw – turnover worthy play analysis, Fields ranks 5th, and the guys around him are a pretty good list, with Ryan Tannehill, Justin Herbert, Andrew Luck, Robert Griffin III, and Mac Jones. That’s certainly not a guarantee, but it’s encouraging.
    • Of course, Fields having the 3rd worst accuracy is not good. Others near him in that category include DeShone Kizer, Geno Smith, Case Keenum, Josh Rosen, and EJ Manuel, which is blech, but Josh Allen and Andrew Luck are right there too, so it’s not necessarily a death sentence on his career.

Data Split By Depth

Like I did earlier in this series, I want to take a little bit closer look at accuracy by splitting it up by depth. It’s harder to throw an accurate pass when it’s further down the field, but those passes carry more value because they gain more yards. Since Fields had a higher average target depth than most, maybe his seeming accuracy issues were really just him throwing deep more often.

The table below shows how Fields compared to the 37 QB sample of rookies with 250+ pass attempts in both frequency and accuracy of passes to different depths of the field. Once again, places where Fields ranked in the top 10 are highlighted in green, while those where he ranked in the bottom 10 are highlighted in red.

A few thoughts:

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Fields in Focus Part VI: Offensive Hindrance

| February 21st, 2022

This piece examines if we can quantify how much the offense around him may have hurt Fields’ production.


Dalton Dropoff

My initial idea was to look at Andy Dalton’s stats in Chicago compared to his previous seasons. Dalton has been on three different teams over the last three years – Cincinnati in 2019, Dallas in 2020, and Chicago in 2021 – so if his performance took a drastic drop in 2021 compared to the previous stops, that would be supporting evidence for the theory that Fields was hurt by the offense around him.

The table below examines Dalton’s efficiency (blue) and playing style (orange) across his last three seasons. Deep throw % is from Pro Football Reference’s Game Play Finder, while all other playing style stats are from Next Gen Stats.

As you can see, there doesn’t actually appear to be much of a change across seasons. Dalton’s sack rate rose a little in Chicago, but he also held the ball a little longer. Besides that, he was pretty much the same bad quarterback in all three years. You can argue Dalton had a similarly bad supporting cast in Cincinnati in 2019, but he played in a really good Dallas offense in 2020, and there is no evidence that going from that to Chicago hindered his performance.


Anecdotal Evidence

Of course, you could make the claim that Dalton is simply a bad QB, and that doesn’t change no matter how good or bad the offense is around him. But that doesn’t help us if we are trying to identify how (or how much) the supporting cast impacted Fields in 2021.

On the surface, it’s reasonable to think that Fields’ stats took a hit due to factors that are outside of his control. Consider the following:

Clearly, it’s fair to say that Fields wasn’t operating in ideal circumstances as a rookie, but how much did that actually hurt his performance? I want to briefly look at three specific areas where Fields appeared to be impacted more than Dalton.

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Fields in Focus Part V: Explosive Plays

| February 18th, 2022

This piece looks at how efficiently Fields helped the offense produce explosive plays. All stats are from Pro Football Reference, with many of them compiled using their Game Play Finder tool.


Setting up the Study

I’ve been tracking explosive plays for several years now because I found they have a strong correlation to total points scored by the offense. Therefore, they’re an important indicator of offensive success; by and large, good offenses produce more explosive plays.

The exact criteria I use for explosive plays are runs that gain 15 or more yards and passes that gain 20 or more yards. This is borrowed from ESPN Stats.

Normally I just track total explosive plays over an entire season, but that’s a little harder to do here since Fields only played in 12 of 17 games, and only started 10 of them. So, I’m going to take a slightly different approach and look at explosive plays per game and per play. I’m going to split the Bears’ season into three groups, and consider each group separately:

  • Games Fields started and finished. There were nine.
  • Games Dalton or Foles started and finished. There were six.
  • Games split between Fields and Dalton. There were two: Cincy (Week 2) and Baltimore (Week 11). These are getting ignored, since I can’t easily figure out who was on the field when explosive plays happened.

This will allow me to compare Fields’ explosive play production to the NFL as a whole, but also to how the exact same offense functioned with a different QB.


Explosive Passes

I want to start with a graph for visual effect, because I think it’s hilarious.

I’ll get to a more typical table with concrete numbers in a second, but for now the graph below shows how many dropbacks (pass attempts + sacks) were needed to produce an explosive pass for all 33 QBs with 200+ passing attempts in 2021. The two Bears samples (Fields and the Dalton/Foles combo) have their dots shown in orange.

As you can see, Fields is right about in the middle of the pack, but look at the Dalton and Foles sample sitting way out to the right by itself! They’re farther away from 32nd place than 32nd is from 1st. Those QBs are truly in a league of their own.

OK, enough making fun of the crappy veteran QBs that Chicago’s last regime somehow thought were the answer to their problems the last 2 off-seasons. Now for some actual numbers. The table below shows this same data as the graph above, but also includes the Bears from 2020 and 2019, so you can see that this is not a new problem for Chicago.

A few thoughts:

  • Chicago’s passing game has been among the least explosive in the NFL for years. I’m not sure if that’s due to bad scheme or bad quarterback play, but in reality, it’s probably a combination of both.

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Fields in Focus Part IV: Rookie Progression

| February 17th, 2022

This piece looks at how Fields’ performance changed as his rookie season wore on. All stats are from Pro Football Focus (PFF) unless otherwise noted.


General Overview

Let’s start with a general look at Fields’ stats over the course of the year. A few quick notes:

  • They are split into three groupings (Weeks 2-5, 6-8, and 9-15), because each group showed some clear distinctions compared to earlier games that I’ll point out below.
  • The first and third groups were considered to be 3.5 games for the per-game stats, because Fields played about half of the Cincinnati (Week 2) and Baltimore (Week 11) games.
  • Basic passing statistics are shown in blue, basic running statistics in orange, and advanced passing style statistics in green. Basic stats are from Pro Football Reference; advanced stats are from Next Gen Stats.

A few thoughts:

  • Those first 3.5 games of Fields’ career were rough. He only completed 50% of his passes, got sacked on 17% of dropbacks, and threw into tight coverage (aggressive throw) over 25% of the time. Basically, he didn’t really know what he was doing. It’s fair to think that being thrown into the fire after the coaches went out of their way to NOT PREPARE him to play during training camp and the preseason hurt him in that regard.
  • Starting in Week 6, there are three drastic changes in how Fields operated that made me group these games differently.
    • The first is that the Bears started relying on him a lot more, which you can see by the big jump in dropbacks/game (includes all pass attempts, sacks, and Fields runs, which were mostly scrambles).
    • In the midst of this heavier usage, you can see Fields running the ball far more often and more effectively, which resulted in his sack rate dropping a bit (though it was still high, the league average was 6%).
    • You can also see Fields’ throws into tight coverage drop significantly, which indicates he was doing a better job of finding open players to throw the ball to.
  • All three of those Week 6 changes continued throughout the rest of the year, but two more significant factors changed starting in Week 9, which caused me to group those final games separately.
    • First, Fields’ yards/attempt mark made a significant jump. It had been fairly steady in the first two samples but was drastically different in Weeks 9 and beyond. This wasn’t driven by just one game, either; three of Fields’ four outings in weeks 9+ featured a yards/attempt greater than 7, a feat which he had only accomplished once in his first 7 games.
      • For a little more context, Fields’ 6.3 yards/attempt mark through Week 8 would have been 28th of 33 QBs with 200+ pass attempts in 2021, while that 7.8 mark would rank 5th.
    • Second, Fields’ time to throw took a massive jump as well. Through Week 8, he was around league average in that 2.75 second range, while the 3.15 seconds he averaged from Week 9 on would have been the highest in the NFL in 2021.
      • Holding the ball too long can be a problem, as it opens you up to sacks, but Fields’ sack rate dropped here. He even threw it into tight coverage less frequently.
      • Coming out of college, Fields was known as a guy who holds the ball and likes to push it deep. In those final few games of his rookie year, we see him figuring out how to make that style work. That bodes very well for the future.

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