SANTA CLARA — Before Christian McCaffrey arrived in 2022, the 49ers under coach Kyle Shanahan were largely a platoon operation at running back.

Matt Breida, Raheem Mostert, Jeff Wilson Jr., Tevin Coleman and others took turns, with carries distributed based on overall health, down and distance and the hot hand.

With both McCaffrey and Jordan Mason on injured reserve as the 49ers head down the stretch, they turned to rookie Isaac Guerendo with some Patrick Taylor Jr. thrown in for good measure and it was one of the highlights of a 38-13 win over the Chicago Bears Sunday at Levi’s Stadium.

It was not only Guerendo’s NFL starting debut, but only the second start of his career since he began college at Wisconsin. It wasn’t until Louisville’s Holiday Bowl last season as a transfer that Guerendo started a game at running back.

“Crazy stat,” 49ers fullback Kyle Juszczyk said.

Guerendo echoed Jusczcyk’s sentiment and credited running back coach Bobby Turner with getting him ready in such a way that nervous butterflies weren’t a problem in stepping in as the lead back.

“The amount that Coach T prepares us allows me to be calm in a situation like that,” Guerendo said. “It’s definitely a crazy stat — second career start in college and the NFL — and it felt good to get the win. I’m happy with that.”

Guerendo finished with 78 yards on 15 carries with touchdown runs of 1 and 4 yards. He also caught two passes for 50 yards from Brock Purdy in the first half on drives that ended in touchdowns as the 49ers jumped to a 24-0 lead, and never looked back in improving their record to 6-7.

Taylor contributed 25 yards on seven attempts and added a 3-yard touchdown to close out the scoring in the fourth quarter. The 49ers rushed for 131 yards and 31 carries with three touchdowns and were 5-for-6 in the red zone, an area that has been the bane of their offensive existence all season.

In the fourth quarter, Guerendo departed with a foot injury and Shanahan said the 49ers were gathering information and hoping for the best.

“I thought Isaac looked real good today,” Shanahan said. “Ran hard, affected the game in the pass game and hopefully we get some good news on his injury.”

Sitting at his locker following the game, Guerendo was putting on his socks and shoes without pain and there was no protective boot in sight.

“Just precautionary,” Guerendo said. ” I feel great.”

Guerendo was stuffed for no gain on the 49ers’ second play from scrimmage but on the next play broke free on a crossing middle screen that went for 23 yards to the Chicago 40. The drive ended on a 7-yard Purdy-to-Jauan Jennings touchdown, the first of two.

On the 49ers’ second scoring drive, Guerendo got loose deep down the right sideline and Purdy hit him for a 27-yard gain to the 1. He then finished it off with his first NFL touchdown and a 14-0 lead.

In the second quarter, Guerendo had a 30-yard burst in a drive that resulted in a 23-yard field goal by Jake Moody to make it 24-0 at the half.

At 6-foot, 221 pounds, Guerendo has near sprinter’s speed — he was a track star and a wide receiver at Avon High in Clayton, Indiana — to go along with power and patience to execute zone scheme runs. He’s also learned the art of staying humble, probably due to the fact that he mostly played in a supporting role at Wisconsin behind Jonathan Taylor and was the No. 2 back at Louisville.

How else to explain Guerendo’s self-analysis for his starting debut?

“I’ve got to apologize to my O-line,” Guerendo said. “I felt like I left some yards out there.”

Because Guerendo was a starter in only his 41st and final game in college, he arrived to the 49ers very fresh physically — although he pulled a hamstring just minutes into training camp.

“The exciting part is I think my best ball is still out there,” Guerendo said. “With limited time in college, I think it’s just exciting to me. I feel like I have more, I feel like I can offer more.”

In high school, Guerendo averaged 23.3 yards per reception with 54 catches or 1,258 yards before switching to running back at Wisconsin. And in his first start, it’s clear the 49ers trust him more in the passing game than they did Mason, who worked diligently on his hands in the offseason but wasn’t often used in the passing game.

“My first question when he was going to start — how well can he catch? Because that’s a big thing in our offense,” tight end George Kittle said. “He proved that today. That catch in the sun, you can’t see anything in that corner, and he caught it. Brock gave him an opportunity on that. All I’ve preached to Isaac — run really, really fast when you get the football and you’ll get a lot of yards.”

Juszczyk said Guerendo, for all his physical gifts, is also a quick study.

“He’s just had good, steady growth,” Juszczyk said. “He’s a really smart guy. He knows when he makes a mistake and I think that’s a really good thing, especially for rookies, when you make a mistake and you’re really unaware of it.”

Taylor was initially on the 53-man roster, then on the practice squad and then called back up after McCaffrey (PCL strain) and Mason (high ankle sprain) went down.

“He hits the right spots, he runs hard,” Shanahan said. “‘He can help us.”

Taylor’s touchdown was his first since 2021 as a member of the Green Bay Packers.

“It’s been a minute, so it felt great,” Taylor said. “It was extremely fun to watch Isaac do his thing, with him being able to come on in the pass game and in the run game and get those two touchdowns. We miss Christian, but we still feel we’ve got some dogs in that running back room and we prepare to be ready when our number is called.”

Originally Published: December 8, 2024 at 6:27 PM PST