Playing the Field(s)

by Paul Sabin|March 23, 2023


The Chicago Bears ended weeks of speculation when they traded the number one overall pick in the 2023 NFL Draft to the Carolina Panthers in return for DJ Moore, a first and second round pick this year, and a first and second round pick in future years. The Bears were able to use their league-leading cap space and draft position to get a number one receiver in DJ Moore, stay in the top 10 of this year’s draft, acquire an additional second round pick this year and two valuable picks in future years, all while signaling confidence in Justin Fields. To the tune of $88 million of surplus value, the Bears may have left negotiations feeling like the long-term winner of this trade.

That surplus value could mean less if Justin Fields fails to further improve as a young quarterback and the Carolina Panthers first overall pick plays exceedingly well. To consider the former, we can look at what we can expect of Justin Fields from an analytics standpoint.

Young QBs vs. Fields

First, we need to take stock of exactly where Justin Fields is as a player. To get there, we must remember how he was viewed entering the league. Fields was a prolific player in college, ranking 2nd in ESPN’s college real plus-minus in his last year at Ohio State. Despite a gutsy performance in the College Football Playoff, Fields was selected 11th overall in the 2021 NFL Draft. Teams such as the Falcons, Lions, and Panthers, who all seem to still be looking for a long-term answer at quarterback, ended up selecting non-quarterbacks. As the fourth quarterback taken in the 2021 draft, it seemed as though the NFL’s evaluation of Fields did not match his elite college production.

Through his first two years playing in Chicago, Fields has had ups and downs. There have been flashes of excellence followed by frustration.

After a historic season on the ground, Fields has had more production running the ball than any quarterback through their first two seasons since at least the year 2000. Fields finds himself at the top of a list that includes Michael Vick, Lamar Jackson, Robert Griffin III, and Cam Newton.

Table showing NFL QB Running Production since 2000


The numbers tell a different story when looking at passing production. Dating back to 2015, Fields ranks 24th in Total EPA versus NFL average amongst first and second year quarterbacks.

Table showing Young QB Production since 2015


Another Hurts?

Now that Justin Fields has a receiving corps comprised of DJ Moore, Chase Claypool, and Darnell Mooney, Chicago hopes to see Fields make similar progress as fellow NFC signal caller Jalen Hurts did this past season after the Eagles secured another elite receiver by trading for A.J. Brown during the 2022 NFL draft.

The comparison to Jalen Hurts’ first two seasons does not end there. According to ESPN’s Total Quarterback Rating (QBR), which was originally developed to be able to account for QB rushing ability, Hurts had a 34 his rookie season followed by a 55 during his sophomore campaign. QBR is measured on a 0-100 scale with a 50 being around average. Fields nearly matched Hurts in his first two years with a 31 and 54 respectively. Each quarterback has averaged running on roughly 25% of their “action” plays the last two seasons and made similar improvements in their production in terms of EPA from year one to year two. The main difference is that Justin Fields started out much worse in his rookie season than Jalen Hurts did.

Chart showing Per Game Contributions, EPA over seasons

Projecting Forward

Historically, quarterbacks have shown most of their statistical improvements by their third year. There tends to still be a small improvement into the late 20s peak years of their careers, but it is much smaller than the leap made in years one through three. This can be viewed by looking at a QB’s EPA vs. NFL average in each season. Strong age projections will account for the selection bias that worse quarterbacks stop getting opportunities as they get older, but the general trend in the first few seasons should be minimally impacted by that.

Chart showing QB Performance by Experience, EPA over Seasons

Fields is not a typical quarterback. He has a strong arm and is the most prolific quarterback on the ground through two seasons in NFL history. Quarterbacks can take advantage of mobility throughout their career, but relying on record-breaking production on the ground may not be sustainable. History provides us a few examples of quarterbacks who succeeded on the ground early on and improved as passers after their first two seasons.

Historically, if a quarterback is more reliant on rushing production (i.e. a negative EPA pass − EPA rush) during his first two seasons, he improves his overall EPA in year three. Conversely, if a quarterback has a positive passing minus rushing EPA through two seasons (like Jared Goff) he has less production the next season.

This result is a combination of relative regression to the mean for both passing and rushing. Rushing has less variance than passing, which means that quarterback rushing production has less variance than quarterback passing production. So, if a quarterback outperforms in rushing, their regression to the mean will be less dramatic than the positive regression to the mean in passing since there is more variance in passing performance. Essentially, running ability gives a quarterback more upside in their passing game than downside in their running game.

Chart showing EPA in Years 1&2 (Average) to Year 3 since 2000

Another way to look at it is to compare the change in passing and rushing EPA from years one and two to year three. While this chart does not clearly show the average trend, it is easy to see how much more change in passing EPA can happen from one year to the next than rushing EPA.

Based on historical trends, it is a fairly safe bet that Justin Fields will be more productive in year three. On average, most quarterbacks are, but that is especially true for quarterbacks that benefitted from their legs in years one and two.

The more interesting consideration is how much better Fields will be in 2023. A modest improvement is the most likely outcome based on historical trends, but that might put the Bears in quarterback purgatory – i.e., having a serviceable quarterback that is not good enough to win it all while still ensuring the team does not have a high enough draft pick to pick a new one. Even with a modest improvement in production, the Bears may play well enough to make noise in the NFC North.

In the best-case scenario, the Bears use the trade and their cap space to emulate the Eagles success in 2022 and become a legitimate challenger in the NFC as Fields and a new look receiving room grow together over the next couple of years.


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