The Kansas City Chiefs are playing January football for the sixth season in a row. But it’s all new to Juan Thornhill.
The second-year pro should have been a key player in the Chiefs’ Super Bowl run last year—he was one for the entire season. New defensive coordinator Steve Spagnuolo prioritized the safety position when he arrived in Kansas City, signing Tyrann Mathieu in free agency and drafting Thornhill with the 63rd overall pick to fill his starting spots. Mathieu and Thornhill brought positional flexibility to the table: Mathieu a famously versatile chess piece in his NFL career, and Thornhill an ex-5 star cornerback recruit turned rangy free safety for the Virginia defense. They dominated on the back end, alternating roles and roaming pre-snap, confusing quarterbacks and covering ground for Spagnuolo’s zone blitz packages.
But in a Week 17 win that secured the Chiefs’ first-round bye, Thornhill tore his ACL. He was out for the season, but the season was already over. He was out for the postseason.
The Chiefs patchworked a solution. The good teams always do. Daniel Sorensen, an experienced veteran, took over the starting role for the postseason. Mathieu spent more time as the deep safety and less time roaming around the box. Cornerback Kendall Fuller took on more of a box role in his stead. Things were dicey at best—they famously gave big leads to the Texans and the Titans, digging themselves into holes that only Patrick Mahomes could somehow escape. That’s typically the Chiefs’ solution to injuries on defense. Just score more.
That’s what they did against the Buffalo Bills in this year’s AFC Championship Game: early mistakes, a quick 9-0 deficit, and then a flurry of points. Their 38-6 scoring run built a multi-score lead as early as the second quarter that they’d never relinquish. But this year, they weren’t swimming upstream. The Chiefs’ defense held the Bills to .011 EPA/dropback, turning one of the league’s most dangerous passing offenses into a below-average one; the week previous, they stymied the Cleveland Browns’ passing game to -.140 EPA/dropback.
The Chiefs brought something to their encore performance that they didn’t have last season: Thornhill. And with him comes a pass defense.
The particular Thornhill the Chiefs brought is important: it’s the healthy one. Thornhill’s ACL tear came in late December, yet he was back on the practice field in August and taking snaps in Week 1, just eight months later. It was clear quickly that Thornhill wasn’t right. He didn’t cover the same ground in centerfield, didn’t explode into contact with the same fearlessness. Missed tackles plagued him early, but the coaching staff kept Thornhill as a starter in the hope that playing time would speed his recovery and boost his confidence.
It didn’t work. Thornhill simply was not healthy enough to make the plays he made in his rookie season; the plays that Spagnuolo’s defense required of him. After the bye week, Thornhill was practically benched. He took a career-low 11 snaps against the Raiders in Week 11 as the veteran Sorensen ramped up to 100% of the snaps. The only game across the final six weeks of the regular season in which Thornhill saw more than 50% of the snaps was in Week 12—against the Tampa Bay Buccaneers.
The new snap count was a reflection of Thornhill’s unfortunate reality: he was not all the way back. Head coach Andy Reid emphasized that they were going to bring him back slowly; Spagnuolo said he and Thornhill had an open conversation about getting his caliber of play back to the levels his rookie season had set, and mutually decided rest was the best path. Running mate Mathieu, sharing the wisdom learned from two ACL tears of his own with Thornhill during his recovery, said that he didn’t feel like himself until a year or two after his injury.
Against the Bills, 13 months removed from the ACL, Thornhill played arguably the best game of his career. No player on defense had a bigger impact in holding the Bills to just 15 points than Thornhill.
Thornhill is the Chiefs’ deep safety. When they’re in their single-high coverage shells, they prefer he’s the centerfielding player. Explosiveness and long speed allow him to affect routes sideline-to-sideline—Thornhill ran a 4.42s 40-yard dash and jumped 44 inches in the vertical; 11 feet, 9 inches in the broad jump—and with a cornerback background, he’s effective addressing the ball at the catch point. Watch as he splits the two vertical stems coming his way, waits until Allen declares his intentions, and then breaks on the route with the ideal angle to play on the football.
Against a team like the Bills, who use light personnel and don’t run it often, the Chiefs want to play Sorensen in the box as a quasi-linebacker. Sorensen doesn’t have the range, angles, or explosiveness that Thornhill has, so dropping him into the box and letting him play underneath zones or man coverage on tight ends better fits his skill set. This leaves Thornhill as the deep player and Mathieu as the box safety in nickel sets.
In those same sets, however, the Chiefs and Spagnuolo incite chaos. They will play Mathieu or Sorensen as deep middle players, which lets them rotate Thornhill into a blitzing or man-coverage role. They’ll rotate to two-high shells and provide help to their outside corners. They’ll play match quarters defenses from the college level that allow their safeties to close aggressively on in-breaking routes. They’ll run aggressive blitzes that force Thornhill to play man coverage from 10, even 12 yards of depth—an extremely difficult ask.
Thornhill can fulfill all of these requirements and did so against the Bills with aplomb. He did not look fearful of contact or hesitant to explode. He was exactly what you want in a defensive back: aggressive, physical, and correct.
This was the impact player that the Chiefs saw in 2019, that helped unlock Mathieu with his versatility and speed. It’s the player the Chiefs will certainly need again when they face the Buccaneers in the Super Bowl.
Remember, the Week 12 Buccaneers game was the only game after the bye week in which Thornhill was on the field for a majority of the snaps (save for the throwaway Week 17 game). That wasn’t an accident. The Chiefs got up early on Tampa Bay, forcing them into a pass-heavy script, to which the Chiefs responded with their three-safety sets. That put Sorensen into the box as a linebacker, which introduced Thornhill as the deep safety.
The Buccaneers attacked Sorensen relentlessly. Rob Gronkowski turned in his lone 100-yard game of the season against the Chiefs, and backup tight end Cameron Brate saw a season-high six targets to boot. Whenever Brady had Sorensen lined up in man coverage against his tight ends, he looked to exploit that matchup. Eventually, the Chiefs started setting Mathieu to Gronkowski in man coverage, to nullify the mismatch.
This is not an uncommon problem for the Chiefs’ defense. In 2019, with good Thornhill in the building, they gave up the fifth-most receiving yards to tight ends on account of a weak linebacker room—but no team gave up fewer yards to receivers. This season, the issue is the same.
The issue is structural. Spagnuolo wants to load the line of scrimmage with creepers—players who could blitz or could drop into coverage—and subsequently rattle quarterbacks into inaccuracies, rash decisions, and panic. It usually works, often forcing quick check-down throws to players like tight ends, who are often afforded free releases against those aggressive fronts.
That knife cuts both ways, however. If the Chiefs’ defense is able to anticipate your hot route and cover it, they can create sacks, incompletions, or even interceptions with their free rushers. Such was the case on this interception from Mathieu. With two potential rushers in the B-gaps, the safeties have rotated to the three-receiver side, indicating to Brady that the pressure is likely coming from linebacker Anthony Hitchens (No. 53). So he slides the protection to that side.
But the pressure is really coming from the opposite side, and accordingly, the Chiefs get a free rusher. Brady is forced to throw hot, as the slot receiver Mike Evans replaces the blitzer and presents his numbers to the quarterback in what seems like open space. But Hitchens is bailing in fast from the opposite side and Mathieu is sitting on top of the route, ready to make a play.
Because of the pressure, this ball ends up bouncing off of Sorensen’s helmet, popping up into the air for an easy interception.
What’s really important about this play is how Spagnuolo manipulated the numbers. By blitzing Sorensen and bringing Hitchens across the formation to cover the hot route, he left three players in isolated man coverage—no safety help—on the open side of the formation. That’s dangerous stuff. The toughest role to fill belonged to Thornhill, who was responsible for Gronkowski with 10 yards of cushion. If Brady had time, that’s the best matchup for the offense.
It speaks to the trust that Spagnuolo has in Thornhill’s coverage ability. That’s why, on a critical early third down, Thornhill’s left in man coverage on Cole Beasley, and makes an astounding play on a scramble drill.
The Chiefs will continue to hammer the Buccaneers with muddied defensive looks and blitz packages. It’s how Spagnuolo played Brady in Week 12, it’s how he played him in the 2008 Super Bowl, and it’s how he’ll play him this Sunday. Those looks are only made possible by the trust he has in Mathieu, Sorensen, and Thornhill to play a variety of different roles with success. In their versatility, he can hide his intentions.
But that defense is volatile, and in that it is only made possible by such players as Thornhill, it’s only made effective and productive by his high-quality play. Without a good Thornhill, the Chiefs would have to ask Sorensen to drop from depth and cover slots and tight ends without much help—that, or surrender their man blitz packages. Without a good Thornhill, the Chiefs wouldn’t be able to play match quarters or stick with their single-high shells to find ways to make Mathieu a robber player. They lose their teeth when Thornhill struggles, and they need a terrible bite to stymie the Buccaneers’ passing attack on Sunday.
Thornhill may be a cog in the machine, but he’s a critical one. They missed him last year, but got the job done—this year, he may be the final piece that cements the Chiefs’ dominance as the modern dynasty atop the AFC and NFL.
- Jun 24, 2022
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