Stanford’s K.J. Costello burst onto scene as Kevin Hogan did in 2012

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When Bryce Love ripped off a 69-yard touchdown run in the fourth quarter of Saturday night’s win over UCLA, it would have been interesting to see what his time was for the sprint. The former track athlete starts fast, then shifts into a higher gear.

Surprisingly, though, he barely had got into the end zone when he was embraced by one of his teammates. And it was … the quarterback?

K.J. Costello, who came off the bench to lead nine scoring possessions, had given the ball to Love on the read option and then continued running downfield.

“Watching the tape,” the redshirt freshman said, “I realized that throughout the game I was playing with a sense of excitement. Also fire. That’s something I want to do all the time.”

On Love’s spectacular touchdown, “I was just doing my job. There was zone-read action, and I was carrying out the fake to try to buy a defender or two off the edge. Bryce ended up cutting it up inside. I just took my fake and followed him down the field.”

Mike Bloomgren, Stanford’s offensive coordinator, wasn’t surprised to see Costello arrive shortly after Love. “He’s only got one knee brace on, and he’s fast,” he said. “He was chasing him. He played with a ton of emotion. I thought the huddle had a ton of emotion around him. It was a lot of fun to see.”

Head coach David Shaw said he’ll wait to see what Keller Chryst’s physical status is before deciding who starts Saturday afternoon against Arizona State. Many Stanford fans already have seen enough. Judging from emails to The Chronicle and Internet chat rooms, Costello is the people’s choice.

Their candidate is 6-foot-5, 217 pounds, and goes by K.J., even though his initials are K.R for Kevin Richard. He’s a Junior, so that’s where the J comes from.

K.J. Costello was an energetic presence against UCLA, leading nine scoring drives and helping a referee make the right call. K.J. Costello was an energetic presence against UCLA, leading nine scoring drives and helping a referee make the right call. Photo: Thearon W. Henderson, Getty Images Photo: Thearon W. Henderson, Getty Images Image 1 of / 1 Caption Close Stanford’s K.J. Costello burst onto scene as Kevin Hogan did in 2012 1 / 1 Back to Gallery

In 2016, he was rated the nation’s 13th- best overall recruit by PrepStar, the 19th by ESPN, which called him the second-best high school pocket passer in the nation. He set 19 school records at Santa Margarita Catholic, many of them held by the Arizona Cardinals’ Carson Palmer, the 2002 Heisman Trophy winner from USC. Costello’s feats included 8,222 career passing yards and 62 touchdown passes. He ran for 19 touchdowns.

He also played basketball and baseball. Oh, and he’s a scratch golfer. Did he ever envision getting on the PGA Tour? “I joke around with my friends that it’s my Plan B.”

Plan A, of course, is the NFL, and he’d like to follow the path of former Cardinal quarterback Kevin Hogan, now with the Cleveland Browns. Hogan was the player on whom Costello focused most closely when he was considering Stanford.

Like Costello, Hogan burst into the consciousness of many college football fans when he came off the bench to lead a scoring explosion. That was in a 48-0 rout at Colorado in 2012, and the Buffaloes couldn’t wait for Hogan to leave town.

Although Costello watched many of Hogan’s games on TV, he said, “I’d be lying if I said I saw that.”

As Hogan did, Costello gives the Stanford offense a run-pass threat that makes defenses refrain from stacking the box against Love.

Unable to find a receiver on a rollout in the second quarter against UCLA, he tucked the ball and found a way to dive for the end-zone pylon a split second before three tacklers hit him.

“If you and I could have bet that his first touchdown in his collegiate career would have been rushing, I would have been on the losing end of that one,” Bloomgren said.

Costello was asked if he wasn’t risking life and limb by taking on three tacklers with a fourth lurking nearby, especially because Stanford was already one quarterback down with Chryst’s injury.

“I do pride myself on protecting myself,” he said. “We talk about it in the quarterback room. We put so much into preparation that one hit is not worth it. But when it’s a gotta-have-it situation, certain rules go out the window when it’s time to make a play for your team.”

As Bloomgren saw it, Costello’s performance Saturday was “spectacular.” And Costello really doesn’t have the playbook completely mastered. The coaches tailored the plays to the ones with which he was most comfortable.

He still needs to work on pre-snap adjustments, Bloomgren said. But with the help of virtual-reality glasses throughout training camp and in the first month of the season, he was able to make up for a lack of repetitions in practice, most of which went to Chryst.

This week, most of the reps are going to Costello.

Tom FitzGerald is a San Francisco Chronicle staff writer. Email: tfitzgerald@sfchronicle.com Twitter: @tomgfitzgerald