He’s a 221-pound human being who runs like a gazelle. Honestly, that’s basically the pitch.
When the San Francisco 49ers traded up to snag him in the fourth round of the 2024 NFL Draft, they weren't just looking for a backup. They were chasing a unicorn. Isaac Guerendo is one of those players who makes scouts drool and then gives coaches a massive headache because they can't figure out where to put him.
Wait. Let’s back up a second.
The Isaac Guerendo NFL Draft story isn't your typical "star college back makes the leap" narrative. It’s way weirder. It involves a position change, a laundry list of injuries, and a 40-yard dash that literally broke the internet for a day.
The Combine Performance That Changed Everything
If you didn’t see the 2024 NFL Combine, you missed the moment Guerendo became a millionaire. He stepped onto the turf in Indy and clocked a 4.33-second 40-yard dash.
Stop. Think about that.
He weighs 221 pounds. Usually, guys that big are built to run through people, not around them. That time was the fastest of any running back in the 2024 class. In fact, it was the fastest 40 for a 220-plus pound back in over two decades. His Relative Athletic Score (RAS) was a staggering 9.98 out of 10.
He’s effectively a linebacker with Olympic sprinter speed.
But here’s the thing—the speed wasn't a fluke. Guerendo was a track star and a former wide receiver. He won Indiana’s "Mr. Football" award as a wideout in high school. He has the hands of a pass-catcher and the frame of a power back. It’s a terrifying combination for a defensive coordinator to look at on film.
The Wisconsin to Louisville Journey
Before the draft, Guerendo was the ultimate "what if" prospect. At Wisconsin, he was buried. It’s hard to get carries when you’re playing behind guys like Jonathan Taylor and Braelon Allen. Plus, the injuries were brutal. We’re talking hamstring issues and a Lisfranc injury that cost him almost an entire season.
He was the king of the 80-yard touchdown run followed by a three-week stint on the injury report.
Transferring to Louisville for his final year was the smartest move he ever made. He didn't even start most of the season—Jawhar Jordan was the lead dog—but Guerendo was the finisher. He averaged 6.1 yards per carry. In the Holiday Bowl against USC, he finally got the start and went nuclear: 161 yards and three touchdowns.
That game was the "aha!" moment for NFL scouts. It proved he could handle a heavy workload without falling apart.
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Why the 49ers Traded Up for Him
Kyle Shanahan loves speed. He craves it.
When the Isaac Guerendo NFL Draft stock started climbing, the 49ers saw a guy who fit their "positionless" offense perfectly. They traded up to the 129th overall pick to make sure no one else grabbed him.
His rookie year in 2024 was a rollercoaster. He started as the RB3, but when Christian McCaffrey and Jordan Mason got banged up, the kid from Indiana got his shot.
- Week 6 at Seattle: He ripped off a 76-yard run to seal the game.
- Week 8 vs. Dallas: His first NFL touchdown.
- Week 14 vs. Chicago: Two rushing touchdowns in his first career start.
He finished his rookie campaign with 420 yards and four scores, averaging a cool 5.0 yards per carry. People were calling him the next Raheem Mostert. The hype was real.
The 2025 Reality Check
Now, this is where it gets a little complicated. If you've been following the Niners lately, you know the "Sophomore Slump" hit Guerendo like a freight train.
Despite a stellar rookie year, 2025 has been... quiet. Really quiet.
Shanahan is notoriously hard on young players. Guerendo reportedly struggled in training camp with a few minor "niggles," and the team didn't wait around. They traded for Brian Robinson Jr. and started leaning on rookie Jordan James.
Suddenly, the 4.33-speed demon was a healthy scratch.
It’s a classic NFL story. One year you're the savior, the next you're fighting for a spot on the kick return unit. But you can't coach 4.33 speed. You just can't. Even though he’s been "iced out" of the offense for much of the 2025 season, his physical tools mean he’s always one injury away from being the most dangerous player on the field.
What scouts got right (and wrong)
Looking back at the scouting reports from his draft cycle, the experts were actually pretty spot on.
They warned about his "upright" running style. Because he’s tall for a back (6-foot), he presents a big target. When he doesn't lower his pads, he gets hit hard. They also worried about his lateral agility. He’s a "one-cut" runner. He wants to plant his foot and go north-south. If you ask him to dance in the backfield, he's going to struggle.
But they were right about the ceiling. When Isaac Guerendo gets into the secondary, nobody is catching him. He’s an angle-killer.
Actionable Insights for Fans and Analysts
So, what do we actually do with all this info?
If you’re a fantasy football player, Guerendo is the ultimate "hold." In dynasty leagues, don't sell low just because 2025 has been a wash. The talent is too high, and he’s still under a cheap rookie contract.
For 49ers fans, be patient. Shanahan’s "doghouse" is a real place, but players usually find their way out. Remember that Guerendo is still one of only 14 people in the U.S. with that last name. He’s unique in every sense of the word.
If you want to track his progress, keep an eye on:
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- Special Teams Snaps: If he’s active on Sundays, he’s still in the plans.
- Pad Level: Watch his highlights; if he starts running lower, he’ll be much harder to tackle.
- Pass Protection: This is usually why Shanahan benches young backs. If he masters the blitz pickup, he’ll be back on the field.
The Isaac Guerendo NFL Draft hype was based on a specific set of physical gifts that don't just disappear. He’s a 221-pound lightning bolt waiting for the right storm to hit.