Reading the Defense, Week 18

The holiday season, after fantasy football's regular season has concluded in most leagues, offers the opportunity to reflect on player results to date and implications for line-ups. Reading the Defense has reviewed defensive tackles this week followed by edge defenders, linebackers, and defensive backs to close out the column for 2023.

Recent History Lessons

Five years ago, the top six defensive backs in fantasy points were all box safeties. Had Budda Baker and Landon Collins stayed healthy, it could have been eight. Cover-3 pass defense dominated usage by defensive coordinators in the second decade of NFL play. Man coverage with one high safety (Cover-1) was also prevalent.

The Seahawks' Legion of Boom defense made Cover-3 famous by dominating the Broncos' high-powered offense led by Peyton Manning in Super Bowl XLVIII. Head coach Pete Carroll's secondary featured potential Hall-of-Famer Earl Thomas at free safety. He was known as a deep centerfielder with tremendous awareness and range. His complement at safety, banger Kam Chancellor, patrolled the box and played shallow zones.

just blessing your TL with some @KamChancellor highlights 😤pic.twitter.com/EMFhcbqhsx

— FanDuel Sportsbook (@FDSportsbook) December 27, 2023

In the summer of 2019, the San Francisco defensive coordinator's seat was hot. Robert Saleh had learned the Cover-3 defense with its 4-3 Under front in Seattle and carried it down the Pacific Coast but was unable to replicate the Seahawks' success. Robert Saleh's unit allowed the fifth-most points in the league in 2018.

Saleh dramatically scaled back the use of the 4-3 Under front in favor of a Double Wide-9 front. The latter deploys two defensive ends who both play well outside of opposing offensive tackles. This change softened the interior of his defense but afforded him another body in coverage. Saleh's 49ers played far less Cover-3 in 2019, opting instead to keep both safeties deep. The team was at the forefront in the growth of Quarters coverage, wherein the two safeties and two cornerbacks are each responsible for a zone covering a deep quarter of the field behind the linebackers. The defensive scheme changes helped propel San Francisco to Super Bowl LIV and Saleh to a head coaching job in New York.

The ramification for fantasy gamers was the loss of a viable defensive back for the game of spreadsheets. Cornerback Richard Sherman paced the group by finishing 57^th among fantasy defensive backs in 2019. The two starting safeties, Jimmie Ward and Jaquiski Tartt, combined for 113 tackles in 25 appearances. Three safeties compiled more than 113 combined tackles by themselves in 2019.

2023 Context

The 49ers were one of several teams that led an evolution toward more coverages with two high safeties. While some teams are migrating toward two-high coverages more aggressively than others, almost every team deploys its safeties more interchangeably than the Seahawks a decade ago.

Man coverage is also in decline throughout the league. In 2018, four units played man more than half the time. In 2023, only one defense utilized man coverage even 40 percent of its defensive snaps. That practitioner, Jim Schwartz of Cleveland, hadn't coordinated a defense since 2020.

Safeties spend so much time in coverage that defensive coordinators contemplate moving them into the slot to attack the line of scrimmage and make more plays. Derwin James Jr., perennially drafted as the top fantasy defensive back, began playing STAR for the Chargers late in the season for this reason. The STAR's alignment most often overhangs the line of scrimmage. His duties involve those of a slot cornerback, an outside linebacker, and a safety. Antoine Winfield Jr made a similar switch in the summer of 2022 but eventually moved back to free safety due to injuries elsewhere in the Buccaneers' secondary.

Incidentally, Winfield leads all defensive backs in fantasy points through 17 weeks. Two more free safeties, Jessie Bates III and Camryn Bynum, trail Winfield. The three are on pace for three of the five best fantasy defensive-back seasons of the past five years.