San Francisco 49ers’ Kyle Juszczyk (44) celebrates his first down catch against the Miami Dolphins in the third quarter at Levi’s Stadium in Santa Clara, Calif., on Sunday, Sept. 20, 2026. (Nhat V. Meyer/Bay Area News Group)
San Francisco 49ers’ Kyle Juszczyk (44) celebrates his first down catch against the Miami Dolphins in the third quarter at Levi’s Stadium in Santa Clara, Calif., on Sunday, Sept. 20, 2026. (Nhat V. Meyer/Bay Area News Group)
Kyle Shanahan didn’t build an offensive empire on sheer genius alone; he built it on an anachronism.
While the rest of modern football treated fullbacks like rotary phones and cassette tapes, Shanahan handed Kyle Juszczyk a huge check and the keys to the car.
It felt indulgent until it became indispensable.
And even when the team felt it became dispensable in March 2025, when the team cut Juszczyk, the Niners quickly sobered up and course corrected.
Because Juszczyk isn’t just an accessory in the San Francisco run game, he’s the fulcrum.
And with Juszczyk out for a few weeks with a sprained knee, the Niners’ run game is going to have to find a new way to move the ball.
Want to know how valuable the Niners’ fullback is? The numbers tell the story.
First, remember the start of the 2025 campaign. San Francisco’s ground attack was a sluggish, predictable chore — arguably the worst in the NFL. Defenses stopped guessing, stacked the box, went wide up front, and dared the 49ers to run right into the brick wall of their own rigid zone-blocking tendencies.
Through the first six weeks of the season, the numbers were an eyesore. San Francisco averaged a miserable 2.97 yards per carry, scratched out one solitary rushing touchdown, and registered a minus-0.154 expected points added per rush. (That’s really bad.) They were living in the negative, churning out a pathetic 38.4 percent success rate on run plays.
To fix the ground game, Shanahan had to un-Shanahan his offense.
Enter the “dash” motion, which might as well be called “Juice” motion.
Instead of lining Juszczyk up in conventional lead spots where downhill linebackers could time his paths like clockwork, Shanahan began moving him all across the formation just before the snap and giving him a running, horizontal start to each play.
It wasn’t just cosmetic flair; it was manufactured confusion.
When Juszczyk fires into that pre-snap glide, defensive fronts panic. Gap responsibilities shift in a split second, angles tilt, and a running lane should crack open before Brock Purdy even has the ball.
“If the timing’s off, they will start going forward before the snap, which is illegal,” Shanahan noted. “But, hopefully the timing’s always on.”
Juszczyk ensured the timing was always on.
And, in turn, the Niners’ midseason rushing turnaround in 2025 was night and day.
Dash motion wasn’t debuted in Week 7’s Sunday Night Football showdown with the Falcons last year, but it did turn into a new foundation for the Niners’ run game in that contest.
From Weeks 7 through 18, San Francisco revamped everything behind that movement. The team’s yards per carry spiked to 4.12, they found the end zone 13 times on the ground, and their EPA per rush flipped from the deep red into the black. The team’s overall run-game down-and-distance success rate jumped to 52.4 percent. (That’s quite good.)
The transformation was even more stark when looking directly at 21 personnel — that one-time anachronism that is en vogue again in 2026.
Over those first six weeks in Shanahan-standard two-back sets, the 49ers managed an abysmal 2.94 yards a pop with zero scores. Once the dash motion took root from Week 7 onward, that mark exploded to 4.18 yards per carry, six touchdowns, and a massive EPA bump.
Most critically, the explosive run rate in 21 personnel more than tripled, leaping from a dormant 3.7 percent all the way to 12.5 percent. In 22 personnel — two tight ends, two backs — explosive carries skyrocketed from literally zero to 11.1 percent.
It turns out that when Juice muddies the waters, Christian McCaffrey has daylight and that’s a dangerous thing for a defense, especially with how spry McCaffrey has looked this season.
Pull Juszczyk out of the equation, though, and the magic trick might just evaporate.
Shanahan knows how precarious this dance is. If Juice is on the sideline — what’s the contingency?
He’ll either have to plunge into the deep end of esoteric playbook madness or trust Brayden Willis and a committee of backup tight ends to fullback cosplay. Neither option inspires much terror in defensive coordinators.
And to have to figure it out against the Seattle defense – a title-winning unit that Shanahan hit with the typically oxymoronic compliment of “sound but aggressive”— no less?
Talk about a test.
Folks will underplay the loss of Juszczyk for Sunday and beyond.
He has four catches. He has no rushing yards. It’s just a fullback — who even needs them?
But how little they know: Juszczyk’s value was never about stat-sheet touches; it’s about the architectural chaos he creates by simply being in the game and executing his task with pinpoint precision. If the 49ers can’t find someone to replace that role or figure out a whole new set of roles before Sunday, they won’t just miss a player — they’ll lose their run-game identity.