Fields in Focus: Introduction and Where He Threw the Ball

Introduction

Justin Fields’ rookie season is over, which means it’s time to evaluate how he did, as well as what it could mean for his career going forward.

Let’s start with a look at the basic stats, which are shown in the table below. In order to give these some more context, I looked at all 33 NFL QBs who had 200 or more pass attempts this year, gave you a feel for the spread of those 33 QBs in each category, and provided Fields’ rank. Cells highlighted in green indicate Fields was in the top 10 for that category, while those highlighted in red indicate Fields was in the bottom 10.

As you can see, this isn’t pretty. Fields ranked in the bottom 5 in every category except yards per passing attempt. It’s definitely a good thing that a quarterback is among the worst in the NFL at completing passes, throwing touchdowns, avoiding interceptions, and avoiding sacks, right? RIGHT?

If you followed the Bears at all closely this year – which I assume applies to most people who read this website – this shouldn’t come as a surprise to you. Fields definitely had his rookie struggles, and we very much see that reflected in the big-picture statistics here.

All in all, I think it’s hard to paint a picture that Fields’ rookie season was anything other than a disappointment. If you had asked me in August if I’d be happy with Fields posting a rookie stat line of 159/270, 1870 yards, 7 TD, 10 INT, 36 sacks, and 12 fumbles, I would have said “no” without even having to think about it. If you’re being honest with yourself, you would have said the same.

But that doesn’t mean Fields’ rookie season was a complete loss. Though the overall results were abysmal, there were some flashes of good present as well, and there are plenty of signs of promise to be found if you’re willing to look. QB play is complicated, and sometimes raw statistics don’t tell the entire story.

That’s where this series comes in. Using a combination of advanced statistics from Next Gen Stats, Pro Football Focus, and Pro Football Reference, I’m going to take a deep dive into Fields’ rookie performance, pointing out the good, the bad, and the ugly. I want to know what he did well, what he needs to do better, and what this might mean for his future.

Rather than make this two or three really long and hard to follow articles, I’m going to break it up into seven sections, each focusing on one specific topic. The general flow will go as follows:

Part 1: Where (and how effectively) Fields threw the ball
Part 2: How Fields did on different types of plays (play action, quick vs. slow-developing, etc.)
Part 3: How Fields performed under pressure
Part 4: How Fields progressed throughout the season
Part 5: How efficiently Fields produced explosive plays
Part 6: How much the rest of Chicago’s offense may have hurt Fields
Part 7: How Fields’ performance compared to other recent rookie QBs

So that’s where this is headed. I’ve already done most of the research, so I know there are plenty of useful insights to be found. I hope you’ll join me on the journey as we discover what there is to learn about the man we all hope is the future of the Chicago Bears.

Where Fields Threw the Ball

Target Frequency

Let’s start with how frequently Fields threw the ball to different areas of the field, sorted by depth. The table below shows this information splitting the field into 4 areas, which I will refer to as behind the line, short (0-9 yards), medium (10-19 yards), and deep (20+ yards) from here on out. Fields’ pass frequency to each area is given, as well as the spread of other NFL QBs who had at least 20% of the pass attempts of the NFL leader. This is how PFF split the data, and it gave a sample size of 39 QBs. Cells highlighted in green indicate Fields was among the top 10 QBs in this region, while those in red indicate Fields was in the bottom 10 QBs.

A few thoughts:

Unsurprisingly, Fields threw to the medium and deep zones more often than most QBs, at the expense of passes behind the line of scrimmage. Anybody who watched him play this year would have guessed as much, and the data bears that out.
Interestingly, this does not exactly match his college profile, when he targeted the medium range quite frequently but didn’t look deep as often as most of his peers.
Fields was a very accurate deep passer in college, so it’s good to see him taking those shots. This is a bit of a spoiler to a future article, but deep passes lead to explosive plays, which are hugely important for an offense’s overall success.

Completion %

Now that we know where Fields threw the ball, let’s take a look at how effective he was throwing to these various depths. We’ll start by examining completion percentage. Like the 1st table above, the table below shows Fields’ completion percentage to each area, compared to the NFL spread of 39 total QBs. Cells highlighted in green indicate Fields was among the top 10 QBs in this region, while those in red indicate Fields was in the bottom 10 QBs.

A few thoughts:

Here we start to see some of Fields’ struggles show up, especially in the shorter zones, where Fields completed fewer passes than the majority of his peers.
The short region (0-9 yards) is especially painful. Fields is 9% below the median QB in completion % here, and this accounted for nearly half of his pass attempts. He needs to get better at the short stuff to help the offense become more consistent.
Fields was right around average in the medium and deep zones, which is very good to see. Deep passing is typically more difficult, so if he’s doing well there, it’s reasonable to think the short stuff will figure itself out over time.
Of course, it takes 2 people to complete a pass – the QB and the pass catcher. It’s possible that Fields’ low completion percentage is due to drops by his pass targets. Pro Football Focus says that 7.6% of Fields’ pass attempts were dropped, compared to an NFL average of 6.2%, which means Fields’ pass catchers cost him 1.4% completions compared to a typical supporting cast. Pro Football Reference tracks drops independently, and they had Fields at 6.9% drops compared to an average of 4.5%, good for a difference of 2.4%. Similar numbers from two different sources provides credibility to the hypothesis that Fields’ supporting cast contributed to his low completion percentage.

Accuracy

In an effort to try and remove drops from the equation, I next looked at how many of Fields’ passes were deemed accurate by PFF. This is admittedly a subjective stat, so there might be a little bit of noise in the data, but the same people are assigning accuracy to all the QBs, so it should be fairly consistent across all of those in the sample.

Once again, the table below shows Fields’ stats at each depth compared to his NFL peers, with cells highlighted in green indicating Fields was in the top 10 (of the 39 QB sample) and cells highlighted in red showing Fields was in the bottom 10.

A few thoughts:

Well that’s not good. Fields was in the bottom 10 of accuracy to 2 of the 4 depth ranges, and just missed on a 3rd. This is actually really surprising, as Fields was graded as one of the most accurate passers to come out of college in the last several drafts.
Once again, we see the short range (0-9 yards) standing out as particularly bad. Fields was the least accurate QB in the NFL to throws in this region. Again, 47% of Fields’ throws went to this depth, so this is a major problem that needs to be sorted out.
Overall, Fields is about 4.4% less accurate than the median QB when you weight his accuracy by % of throws to each region. This makes him one of the least accurate QBs in the NFL (only 2 in the 39 QB sample were worse).
One stat we can compare this to is completion percentage over expectation (CPOE), which looks at how many passes Fields completed compared to how many an average QB would be expected to complete given the location and movement of all offensive and defensive players at the time of each pass. Fields had a CPOE of -2.0%, meaning he completed 2% fewer passes than an average QB would be expected to. This is better than the -4.4% in expected accuracy, and points to perhaps Fields’ pass catchers not hurting him excessively with drops (CPOE stats from RBSDM).
I think it’s fair to question how much of an impact not getting to practice at all with the WRs he’d be throwing to in training camp hindered Fields, especially early in the season. I don’t want to say more for now, because I’ll have a separate article later in this series specifically focusing on how Fields’ production changed throughout the season.

Full Breakdown

Finally, I want to break up each depth into left, center, and right in order to get a feel for whether Fields’ struggles were focused on any part of the field horizontally in addition to vertically. This gives us 12 zones (4 depths x 3 zones for the left, center, and right of each depth). The table below shows how frequently Fields targeted each zone, as well as how effectively he threw it there, as measured in accuracy rate and yards/attempt. All data is compared to other NFL QBs, with green cells indicating Fields ranked in the top 10 and red showing Fields was in the bottom 10 (out of 39 QBs).

A few thoughts:

Some of the zones here have sample sizes that are too small to think much about. For instance, Fields had 2 targets to the left side behind the line of scrimmage, and 3 targets to the right. I don’t put much weight in that data.
The short middle of the field is the most targeted, accounting for 1/4 of Fields throws (which is on the low end for NFL QBs). It’s also where Fields was at his worst, finishing last in the NFL in accuracy and near the bottom in yards/attempt. He needs to be able to throw efficiently here given how many throws are headed into this region.
Fields also struggled down the middle of the field in the medium range (10-19 yards). It’s not unusual for a young QB to struggle in the middle of the field, where there is more traffic and the adjustment to the speed of NFL defenders is greater. Rookie QBs show the most improvement from year 1 to year 2 throwing in the middle of the field, and the Bears will very much need Fields to make a big jump in that area.
If you remove the middle of the field, Fields was actually above average throwing to the medium zone. So it really is all about that middle of the field section. Besides that middle-medium zone, Fields was good throwing deep and medium pretty much across the board, which is really good to see.

Lessons Learned

I’m now 1800 words in, with 5 tables full of data. Let’s take a step back and summarize the the main takeaways from this article:

Field’s tendency to throw deep and medium both frequently and accurately mostly translated from college to the NFL.
Fields really struggled throwing it short, and also struggled mightily throwing to the middle of the field. Those are areas that need to show drastic improvement going forward if Fields is going to be a reliable starting QB in Chicago.
In general, this explains why Fields’ rookie season was so high variance. He was good at a lot of the hard stuff (deep passes), but struggled with the short stuff, which is supposed to be easier. That’s a big part of why Chicago’s offense was so inconsistent. You need to be able to get the consistent small gains in addition to hitting on the chunk plays. Fields has the chunk plays down, but now must become more consistent underneath.