Reading the Defense: Week 18

Reading the Defense is a weekly column that considers the effects of player deployment and schematic trends on individual defensive players' fantasy value. While analytics take hold in NFL front offices and sidelines, data-driven decision-making also benefits fantasy gamers.

Looking for Lessons

One week remains in the NFL regular season while most fantasy leagues have concluded their seasons. As many fantasy gamers' roster management ends, this column looks back on the 2024 season for lessons to glean for future application. Week 16's edition focused on linebackers. Defensive linemen appeared last week. The 2024 series of Reading the Defense concludes with the defensive backfield.

Eight players from NFL secondaries rank among the position group's top 25 scorers in both 2024 and 2023. Quite notably, eight defensive linemen also appear on both year's leaderboards. While the total of eight is low for linemen, it's more typical in the secondary. Based on historical data, repeat performances are statistically less likely by defensive backs than defensive linemen. In 2023, only four defensive backs repeated top-25 finishes.

Year-over-year consistency is rarer in the defensive backfield for two reasons. First, the position group scores fewer points per full-time player than linebackers. More simply, they make fewer tackles because they line up farther from the football at the snap.

Second, far more defensive backs play full-time than linebackers. Even within the secondary, more safeties play full-time than linebackers, and more cornerbacks play full-time than linebackers.

As a result, scoring at the position is flat. The margins between players' scoring is miniscule beyond the top few players. Highly unpredictable occurrences like defensive touchdowns make big differences in fantasy scoring. DaRon Bland burst onto the scene and into the top ten last year with five TDs. Without these 30 points, he resides 16 spots lower.

The small margins and variability at the position fueled a discussion internal to the Footballguys IDP team as to whether a player with a preseason rank or ADP of 10 could be undervalued. In a universe including more than 100 full-time players, forecasting 5th versus 10th seems like splitting hairs. Patrick Mahomes II's rank of 10th among quarterbacks is a much bigger disappointment than 17th-ranked Derwin James Jr. Mahomes is 8.4 points per game behind top-ranked Lamar Jackson, while James is 2.4 points per game behind defensive backfield leader Budda Baker.

A Throwback Season?

The top 13 defensive backs in fantasy points on the Footballguys leaderboard are all safeties on teams that lean single-high in their coverage choices. Through 2018, safeties always dominated defensive backfield fantasy scoring. A safety was categorically preferable to a cornerback in fantasy football.

Logan Ryan broke through in 2019 as a nickelback for the Titans, leading all defensive backs in fantasy points. NFL passing games were approaching historical heights in production. In 2020, defenses began using more two-high-safety coverages to combat big plays. With both safeties deep, nickelbacks took on more responsibility in run defense and blitzing. The intent to disguise coverages required each safety to operate more interchangeably. In 2018, players like Keanu Neal and Landon Collins routinely played low while their counterparts played high. Since then, disparities in deployment between safeties on the same team have shrunken; meanwhile, leaguewide passing yardage has declined precipitously since 2020.

In his rookie season for the Raiders, Tre'von Moehrig played 1,058 of his 1,152 snaps deep, according to Pro Football Focus. His role has evolved to include more frequent alignment nearer the line of scrimmage in each of the three years since. He played the plurality of his snaps in the box in 2024 for the first time. His increased proximity to the football helps fuel his position of 13th among fantasy defensive backs.

What's remarkable about Moehrig's evolution in deployment is not the gross increase in box snaps but rather the divergence in deployment relative to his running mate from 2023 to 2024. First Marcus Epps and then Isaiah Pola-Mao played mostly deep alongside Moehrig this year. This disparity is reminiscent of 2018. Any foreshadowing in Las Vegas of this evolution in game planning escaped this writer's attention.

Current Giants defensive coordinator Shane Bowen deployed a predominantly left-right defensive system in Tennessee from 2021 to 2023 that made only marginal discrepancies in safety deployment. The Giants drafted Tyler Nubin to play alongside incumbent starter Jason Pinnock. The only evidence that the veteran would occupy a predominantly deep role appeared in a scant 20 preseason snaps. In his more diverse role, Nubin likely would have finished among the top 25-scoring fantasy defensive backs had he remained healthy.

Gus Bradley is arguably the NFL's last remaining defensive coordinator using a scheme substantially similar to those of the previous decade in which the box role and deep role are clearly disparate and disparately occupied. Bradley threw fantasy gamers off by switching his free safety, Nick Cross, with his strong safety, Julian Blackmon, early in the season after a multi-week injury to the incumbent starter Blackmon. Cross ranks second among fantasy defensive backs thanks in part to optimal deployment.

Those taking issue with the opening statement of the last paragraph would name Teryl Austin. Pittsburgh runs more single-high safety coverages than anyone. DeShon Elliott was the first Steelers strong safety to capitalize on this optimal deployment in a decade. He sits at 12th on the Footballguys leaderboard despite missing two games.

#FFIDP - Safety tackle efficiency by defensive alignment (2021-2023), per @PFF:

BOX: 11.1% ?
WIDE: 10.4% ?‍??
SLOT: 9.6% ?

-- Average: 9.1% --

DEEP: 8.5% ?
DL: 7.9% ?

— Jon Macri (@PFF_Macri) June 4, 2024