Greatest NFL defensive coordinator of all time? Chiefs' Steve Spagnuolo presents compelling case

Steve Spagnuolo is about to appear in his fourth Super Bowl in five seasons as the Kansas City Chiefs’ defensive coordinator. Yes, coaching for a team that rosters one of the greatest quarterbacks of all time certainly helps the résumé. But over the course of his five-year tenure, Spagnuolo has transformed K.C.’s defense from a liability to the strength of this squad. Already the only coordinator to win Super Bowls with multiple franchises (New York Giants and Chiefs), Spagnuolo can become the only one with four rings on Sunday.

With those accolades in mind, should Spagnuolo be considered the greatest defensive coordinator in NFL history?

It took Spagnuolo a quarter century of coaching to get his first gig calling plays in the NFL, but he seized the opportunity immediately. In his very first season as defensive coordinator of the New York Giants, Spagnuolo was essential to Big Blue pulling off one of the league’s most improbable Super Bowl triumphs. That 2007-08 run culminated in a masterclass performance where Spagnuolo’s defense held the second-highest scoring offense in NFL history to 14 points and spoiled the New England Patriots’ undefeated season.

As impressive as Spagnuolo’s debut season as an NFL DC was, this year’s coaching job might be even more extraordinary. With these Chiefs becoming the second team in NFL history to reach the Super Bowl in a season in which they had the NFL’s youngest defense — joining the 2009 Indianapolis Colts — Spagnuolo has built a juggernaut from the ground up. And as Kansas City’s offense has taken a step back this season — ranking outside the top five of expected points added per play for the first time in Patrick Mahomes‘ career — Spagnuolo’s defense has surged to become a top-five unit by the same metric.

After Sunday, when Kansas City takes on the San Francisco 49ers in Super Bowl LVIII, the Chiefs will have faced four of the top six offenses by points scored this season during their playoff run. So far, Spagnuolo’s unit has held those opposing offenses to a paltry average of 13.7 points per game, the fourth-lowest allowed by any team that made the Super Bowl in this millennium. Spagnuolo’s final test is one of the most explosive offenses this league has ever seen, as this year’s iteration of the 49ers averaged 6.6 yards per play, the seventh-most by an offense in the Super Bowl era. Kyle Shanahan has built a death star defined by interchangeable personnel, misdirection and explosive plays. In many ways, Spagnuolo’s unit presents the defensive mirror image.

With all the communication and vast knowledge required to execute Spagnuolo’s intricate scheme of coverage rotations and disguised pressure packages, the success of the Chiefs’ young D is a testament to the developmental work of this coaching staff. Much like the 49ers do on offense, the Chiefs move around their defensive players situationally to create matchups and mask their play calls. The secondary drops into split-safety coverages more often than any other team in the NFL, but opponents rarely know who will end up being responsible for each deep half of the field.

This multiplicity has been essential to generating pressure without elite edge-rushing talent. Second-year cornerback Trent McDuffie will align in the slot when the defense brings on extra defensive backs, weaponizing his ability as a pass rusher. McDuffie generated 14 unblocked pressures this season, more than double any other cornerback. Spagnuolo creates one-on-one matchups for star defensive tackle Chris Jones by manipulating pass-protection schemes and bumping him to the edge in obvious passing situations. Jones generated 56 pressures in one-on-one matchups this season, five more than any other defensive tackle. Perhaps his most impactful pressure of the year came on a bull rush from the edge during the Buffalo Bills’ final drive of the Divisional Round, preventing a go-ahead touchdown.

In the same way that many of the most lethal offenses today have fine-tuned their timing to maximize the effectiveness of pre-snap motion, Spagnuolo’s defenders wait until the last possible moment to show their hand. The proof is in the pudding, as the Chiefs generated a league-high 73 unblocked pressures this season and have ranked in the top seven in every season with Spagnuolo at the helm.

The young unit’s elite 2023 performance is even more impressive given how unique its defensive scheme is relative to the rest of the NFL. For most teams in the league, it is standard to send a five-man pressure package while playing with a single-high safety in coverage on the back end. This ensures that there are more bodies in the short and intermediate areas of the field, taking away quick options for the quarterback. This year’s Chiefs defense, however, was the first to play split-safety coverages behind a majority of its five-man rushes dating back to 2018. The 2023 Chiefs ran a total of 90 plays combining a five-man rush with split-safety coverage, 35 more than the next-closest defense.

Spagnuolo’s propensity to send extra pass rushers puts more pressure on the coverage to hold up with fewer resources. Again, these young defenders have proven to be wise beyond their years — another demonstration of their homegrown player development. Every player on the back end who logged triple-digit snaps outside of cornerback L’Jarius Sneed was brought in over the last two offseasons. Five of those seven were drafted: corners McDuffie, Joshua Williams and Jaylen Watson, and safeties Bryan Cook and Chamarri Conner. Sneed, a 2020 fourth-round pick of the Chiefs, has developed into a lockdown corner under Spagnuolo’s watch, shadowing top receivers in a league-high seven games this season, per NGS.

Looking forward to the matchup on Super Bowl Sunday, Kansas City’s defense is particularly well-equipped to handle San Francisco’s attack in one critical aspect: The Chiefs’ swarming secondary has been among the best at limiting explosive pass plays and yards after the catch. Facing off against a 49ers offense that comfortably led the NFL in YAC over expected (+710, the only offense over +500), preventing explosive gains after the catch will be crucial to the Chiefs’ defensive success. This is a strength-on-strength matchup: The 49ers led the NFL with 28 receptions that gained at least 20 yards after the catch, while the Chiefs’ defense allowed the fewest such plays (six). Even when sending extra pass rushers, the Chiefs were the only defense to allow fewer yards after the catch than expected.

Kansas City’s defense is well-equipped to slow down San Francisco’s historic offense. If Spagnuolo and his unit can execute upon this opportunity, the coach should cement himself on the Mount Rushmore of defensive play-callers. And could that be enough to send him to Canton?