Film review: What to make of the Chiefs’ rollercoaster run defense

Over their last three games, the Kansas City Chiefs‘ opponents had one thing in common: impressive rushing performances. The Las Vegas Raiders, Buffalo Bills, and San Francisco 49ers each totaled more than 100 rushing yards. Still, only one of those games resulted in a loss — and it didn’t seem like Buffalo’s running game was the main culprit.

Despite the gashes it has taken on the ground, Kansas City has allowed the second-fewest total rushing yards this season, while also conceding the seventh-lowest rushing yards per attempt (4.2).

Through seven games, this up-and-down performance has been a storyline — but how much has it actually affected the team’s success? Let’s take a closer look.

The cracks in the strategy

When an offense sends fewer than three wide receivers to the huddle — whether that entails an extra running back or an extra tight end — Chiefs defensive coordinator Steve Spagnuolo will match with his base package. That’s a traditional 4-3 formation that relies on four defensive linemen and three linebackers. This gives each man a gap to defend against the run.

Kansas City’s last three opponents have sometimes exploited this tendency by passing out of these looks — an obvious way to take advantage of that particular alightment. The bigger problem is that teams have also found success running against the base.

It started with the Raiders, when they challenged Kansas City’s three linebackers — especially rookie Leo Chenal — on downhill runs with a fullback as the lead blocker.

On the first two plays shown here, Chenal engages the blocks passively (and without effective gap discipline), allowing himself to be cleared from the running lane. In each case, this leads to a big play.

Early in their games against the Chiefs, the Bills and 49ers also had success using these power runs, carving out chunks of seven or more yards much too often.

Kansas City’s front four can make life easier for its second-level teammates by holding the wall and preventing penetration — whether that’s from a blocker trying to reach a linebacker or a ball carrier. That starts with the nose tackle, who is tasked with absorbing double teams — and on many running plays, occupying two offensive linemen.

Chiefs defensive tackle Derrick Nnadi has filled this selfless role for most of the Spagnuolo era. But this year, he doesn’t appear as stout at the point of attack. More often than not, he ends up losing his ground — giving the offense space between the tackles.

Nnadi’s failed plays will allow a guard to more easily engage with a linebacker early in a play’s development, allowing the offense to smoothly seal off the desired running lane.

Potential adjustments

After reflecting on it during the bye week, I’ve come to the conclusion that the Chiefs should make some tweaks to their run defense. The first one is very simple: get defensive tackle Khalen Saunders on the field more often.

The rotational lineman leads the entire defensive line in tackles — despite playing only 34% of the defensive snaps. Saunders has made a handful of plays by displaying the very quick first step that made him an exciting draft prospect — but this year, he appears to have become stronger (and more powerful) with his hands.

Saunders’ improved ability to control blocks at the line of scrimmage allows him to effectively occupy two gaps — so when he initially penetrates one, he can still recover to the other. That’s where his powerful hands come in: by combining them with strong torque, he can move an offensive lineman’s weight around more easily than an average defensive tackle makes it look.

Currently, Saunders comes in when Chris Jones needs a breather on running downs. I believe he could be paired with Jones on the line, substituting for Nnadi more often.

At times during the last two weeks, Spagnuolo has already been testing another adjustment: matching an offense’s heavier personnel with his base defense less often. Instead, he’s used nickel personnel — where five defensive backs boost coverage potential — and had slot cornerback L’Jarius Sneed act as an outside linebacker to fill run responsibilities.

Sneed’s short-area burst (and explosiveness) translate to taking on blocks with strength and making tough tackles around the box.

What it means moving forward

As frustrating as they are to watch, these flaws in the team’s run defense haven’t yet cost it any games. In many weeks, the Chiefs have been able turn the game into a shootout, pressuring opposing offenses to score quickly by passing more — even if its running game has been productive.

The Kansas City offense will continue to make games play out that way, which reduces the relative importance of consistently stifling an oppenent’s running game. Instead, the unit’s main responsibility is to make big plays here and there — whether it’s a tackle behind the line of scrimmage on first down or stuffing a short-yardage run on third or fourth down.

With linebackers Nick Bolton and Willie Gay Jr. — now back from his suspension — the Chiefs have the two playmakers who can do that. Once he finds the lane to the ball carrier, Bolton — the team’s leading tackler — is a heat-seeking missile. He and Gay will be the ones making these game-changing plays.

The bottom line

Sometimes, Kansas City’s defense has looked really good against the run. Other times, it has been very vulnerable. The unit’s job won’t get any easier against the Tennessee Titans in Week 9.

That said, the Chiefs don’t need to have the NFL’s best run defense. They only need to make a few big plays in each game — while also preventing explosive runs. In the last few weeks, they’ve struggled to do those things. But a few tweaks to the lineup — including Gay’s return — could tie up those loose ends.