NFL Plus/Minus: Myles Garrett is the Defensive Player of the Year (Again)

Using historical on-off the field splits and player clustering to estimate value of defenders

In this post, I’m going to detail the methodology and results applying my NFL Plus/Minus metric to defenders this season, which includes many of the top candidates for NFL honors, including Defensive Player of the Year and All-Pro selections, plus some names you might not expect.

My NFL Plus/Minus methodology will evolve as time goes on, and the results will also change. Even so, the first runs of results over the last two years point to a few potential gaps in our current understanding of where defender value comes from, and give us some ideas on how to apply historical on/off splits to make assumptions about the broader values of different position groups.

Last week I detailed the NFL Plus/Minus methodology and results for all non-quarterback offensive players (showing that longshot Offensive Player of the Year Ja’Marr Chase is probably the most valuable non-quarterback, not Saquon Barkley), and in this post we turn to defenders. It’s more difficult to find relevant, objective metrics to judge defenders than we have for offensive players, specifically offensive skill position players. Therefore, there’s a higher reliance on PFF grading in this analysis, especially for run defense, and coverage to a lesser degree.

METHODOLOGY

Using participation data and on- and off-the-field splits have a rich history in other sports for building player valuation metrics. No matter how much we try, the human eye and brain cannot notice the contribution to every player on every play while calculating the exact impact of those actions on the game in a comparable metric. By studying the differences in team success — in this case, using expected points added — when a player is on and off the field, we can capture the entire effect in useful numbers for comparison.

The issue with using on-off splits in football is the time for all players on the field is limited in a 17-game season, and the substitution patterns for different positions don’t allow for much comparison. Without injury, cornerbacks can play every snap of the game, whereas certain interior defenders are rotated consistently. The solution I came up with was to look at the on-off splits of groups of similar players rather than individual players.

I used the nflreadR participation data going back to 2016 — along with other traditional and advanced stats — to cluster similar players for each position in each facet of the game and then compiled the on-off splits of those groups. In doing so, we increase the total samples of measurement and reduce the noise of single-player numbers.

Before we get into the results of the analysis for every defensive position, let’s walk through a specific example of how clustering works, using the coverage facet for cornerbacks.

Without getting bogged down in the details, the graph above divides all cornerback seasons with at least 25 coverage snaps from 2016 to 2024 into five different color-coded clusters. The metrics used to group the clusters include coverage grade, percentage of snaps targeted and percentage of snaps in the slot. This is a simplified version of the actual clusters used in the analysis, which are more numerous and contain fewer players per cluster.

I’ve highlighted a handful of cornerback seasons from 2024, showing that young studs like Derek Stingley Jr. and Patrick Surtain are in the direction of higher grading, and the opposite direction of higher yard and touchdown rate (per coverage snaps) where Marcellas Dial resides. Cooper DeJean is an example of a strong slot corner, which falls in the lower lefthand side. Charvarius Ward ended up disappointing a bit as an average-ish coverage player by most metrics.

Once we have players assigned in clusters, we total up the team-level expected points added with the clustered players on- and off-the-field then come up with a per-attempt number for the average value added by that cluster versus their teams giving coverage snaps to other cornerbacks.

Unsurprisingly, historical on-off splits show that teams miss cornerbacks like Stingley and Surtain when they’re off the field. There’s also a material positive effect for the DeJean cluster, though not to the same level.

For the NFL Plus/Minus results, this exercise of clustering by role is applied to every position in all three facets of defensive play: pass rush, run defense and coverage. The results below detail the points prevented (negative is good) numbers for the top-10 defenders in every position group and then the top-12 overall. I’ll post more commentary after the results and how I’m thinking about them.

It was another strong year for value with interior defenders. My draft research found that the position group is in the top tier for draft value with offensive tackles and edge rushers, particularly for those who can affect games rushing the passer.

The metrics used to form player clusters for pass rush value are pass-rush win rate (via PFF), sack rate, pressure rate and pass rush grades (PFF). For run defense, the other major component of interior defender play, the metrics are PFF’s run defense grade, “stop percentage” (tackles that constitute a "failure" for the offense), and missed tackle rate.

Cam Heyward tops the list for interior defender value, which aligns with All-Pro numbers that saw him tally more first-place selections and overall voting points than any other interior lineman. But AP voters weren’t as positive on Heyward as this analysis, with 21 of 50 voters not assigning Heyward one of the two First-Team slots.

There’s a material gap down to Leonard Williams at second most valuable. Williams didn’t make the First- or Second-Team All-Pro rosters, ending up fifth in voting. Williams’ 2.3% sack rate was his strongest since the 2020 season.

Chris Jones was my most valuable defensive player by NFL Plus/Minus two years ago, but my numbers this year show him as having an elite, but not top-notch season. Jones was strong as ever adding value in pressuring the quarterback, but his run defense value was fairly limited. I’m perfectly fine with Jones getting another First-Team All-Pro selection this year, though there’s some evidence his reputation pushed him a bit higher in the minds of voters than objective performance.