Kyle Shanahan-Brian Flores showdown should be a highlight of 49ers-Vikings rematch

Think of an optical illusion, one of those drawings with multicolored lines, that changes based on your angle. They’re wondrous shapes, created in ways that are almost impossible to understand.

Kyle Shanahan’s run game is the football version of them.

Studying the San Francisco 49ers’ ground attack is like fixating on one of these images. Is this player moving there for a reason? Or is this player moving there to make you think there is a reason? Only the artist truly knows.

What elevates Shanahan’s choreography is a combination of consistency and physicality. Offensive linemen flow to one side, and skill players drift to the other. And as they all move in harmony, they smash into opposing players with technique and force.

Call it beautiful violence. Call it disciplined aggression. Call it whatever you want. But whatever you call it, know that it’s going to lead to yards and points.

Last year, the 49ers led the NFL in rushing efficiency and explosiveness. Last week, without arguably the most important character in Shanahan’s production, Christian McCaffrey, San Francisco still ran for 180 yards and averaged nearly 5 yards per carry.

“I mean, it really doesn’t get more challenging,” Minnesota Vikings defensive coordinator Brian Flores said earlier this week.

Harrison Phillips, the Vikings’ preeminent run stopper, breathed deeply when asked to expound on the challenge.

“They don’t have tendencies,” Phillips said. “For the four plays they run one way, they’ve run four plays the other way. They go strong, they go open, they go four out, they go condensed — everything they have an answer for, so you cannot guess.”

. @horribleharry99 speaks on the support he has received after contract extension pic.twitter.com/R43V88oKOK

— Minnesota Vikings (@Vikings) September 11, 2024

Dissecting the illusion and diffusing the force requires a different kind of acuity, and no team displayed this better in the 2023 regular season than the Vikings. On “Monday Night Football” in Week 7, Flores’ defense limited the 49ers to zero explosive runs and their lowest yards per carry average of the season.

How did they do it? Does last year’s plan apply to 2024? And if not, what approach will the Vikings take this time around? Maintaining the momentum Minnesota has generated early this season might hinge on the answers to these questions.

Let’s start our study with a statistic: The 49ers averaged 1.53 yards after contact per rush in last year’s matchup with the Vikings, which was their lowest mark of the 2023 season, according to TruMedia.

A review of the game film shows that the Vikings, especially on early downs, used quasi-six-man fronts with three true defensive tackles: Phillips, Jonathan Bullard and Dean Lowry. They clogged interior gaps while edge rushers Danielle Hunter and D.J. Wonnum — and usually a safety like Josh Metellus or Harrison Smith — anchored the edges of the line of scrimmage.

Here is what that looked like from a first-and-10 situation in the second quarter:

Phillips, who signed a two-year extension this week, recorded the second-most “stops” in the NFL among interior defenders last year, according to Pro Football Focus. Stops are a metric of tackles that constitute “failure” for the offense. Bullard ranked 13th in the league in stops, indicating his own reliability against the run.

Add off-ball linebacker Jordan Hicks’ awareness and gap integrity as well as cornerback Akayleb Evans’ willingness to join the tackling party, and Minnesota’s success starts to make sense. It might all sound repeatable, but another pivotal factor was at play: The Vikings grasped an early lead, placing the 49ers in clear passing circumstances.

The 49ers were about 20 percent more likely to throw the ball in 2023 when they trailed than when they led. On Wednesday, Vikings head coach Kevin O’Connell referenced this reality.

“If we don’t capture the momentum of the football game,” O’Connell said, “you could see 40-plus runs out of Kyle and this group.”

So, how applicable is last year’s plan?

“It’s all relevant, to a degree,” Flores said this week.

But he also admitted, “Things are a little different.”

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There have been personnel alterations on both sides. Last year, 49ers wide receiver Deebo Samuel missed the Week 7 game with a shoulder injury. This year, the 49ers might not have McCaffrey. The Vikings, meanwhile, replaced Lowry with Jerry Tillery and discarded Hunter and Wonnum for Jonathan Greenard and Andrew Van Ginkel. They also swapped Hicks for Blake Cashman and relegated Evans to the bench for experienced veterans Stephon Gilmore and Shaq Griffin.

These are upgrades for Minnesota in most cases that provide Flores with an entirely revamped machine to work with. He has, in essence, sold an old stick shift that he made work and purchased a new truck with a sleek dashboard, rear camera and heated seats.

But that doesn’t mean he’s going to drive it any differently. At his core, Flores is a man who wants to put quarterbacks’ minds in a blender. It’s just that the current fruits allow for different smoothie flavors than before. This is already evident. The Vikings rushed four defenders on 75.5 percent of the snaps in Week 1. Last year, the Vikings did not deploy a four-man pass rush for more than 50 percent of the snaps in any individual game.

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To summarize, Flores can and will break past tendencies. You watch a Vikings defender float across the field, and you wonder if he is moving for a reason or moving to make you think there is a reason. If this sounds like a mirror of Shanahan’s offense, well …

“How their offense plays kind of reminds us of the way we play defense,” said Vikings safety/linebacker/cornerback Josh Metellus.

Sunday’s game is optical illusionist versus optical illusionist, two of the game’s best thinkers who value many of the same things going mano a mano. What approach will the Vikings take this time around? When you ask players like Phillips and Metellus, they respond with big-picture ideas like “physicality,” “discipline” and “winning one-on-one matchups” — qualities instilled by these coaches as their foundation long before any of the deception begins.