About two and a half hours prior to kickoff at each home game, cheers and fight songs bombard the Cal football team on Piedmont Avenue as it makes its way toward Memorial Stadium. The tradition is called March to Victory.

Zach Kline has his own tradition. Tuning out the rest of the world, he lets the opening riff of “Black Thumbnail” by Kings of Leon fill his head before his team leaves the bus. The first stanza is a simple yet seductive formula of rollicking guitar and scratchy voice.

“Such a sweet song,” he says.

More often than not, pumping himself up before a game means staying in that state of mind for the entire game. Getting into the zone isn’t a first step that gives way to an adrenaline rush on the field.

On most Saturdays, it’s the only step. Kline has to cling to that pregame emotion even as the quarters wind down. Just in case the coaches decide to sub him in.

As the No. 2 quarterback on the team, Kline rarely sees playing time. Between the lines of “Black Thumbnail,” he dials into the emotions that other teammates will harness throughout the next 60 minutes. He stays vigilant as someone ahead of him calls the shots.

For Kline to do so wasn’t part of anybody’s original plan. When he came to UC Berkeley in spring 2012, he was Cal’s great hope. But a quarterback race in this past offseason left him on the sideline for the second year in a row.

His position on the team could be seen as anticlimactic. Or it could be seen as a vital, if less visible, cog in Cal’s machine.

Kline sees it as the latter.

Before the quarterback competition, there was something simpler: Zach, his father and the park.

Scott Kline used to take his 8-year-old son to a nearby park year-round in Danville, Calif., to play football and baseball. That same year, Zach joined his first Pop Warner team, the San Ramon Bears.

Scott taught his son a simple three-step drop in the hopes it would get Zach noticed in practice. It did: That first year, Zach switched from linebacker to backup quarterback.

From then on, at the beginning of every new season, coaches would ask which players wanted to try out for quarterback. After a while, it served little more than symbolic purpose; Kline always won the starting slot.

“Fifty hands would go up,” says Lisa, Zach’s mother. “There was always a competition, and he beat them out.”

Kline has always been an entertainer — when he was 3 years old, he re-enacted the “Greased Lightning” dance in full costume while his older sister, Aly, got it on tape.

Performing on the field came naturally and brought with it plenty of attention. Adults constantly told him he would have a career in college, in the pros.

So one day at the park, Scott Kline imparted some advice his young son never shook off. If you ever get the chance to play in college, he told Zach, and Cal or Stanford comes calling, just say yes. There are no better schools.

Danville lies 30 minutes and two freeways southeast of Berkeley. Kline grew up attending games and youth camps in Memorial Stadium, so dreams of playing there came easily.

“I was all Cal,” he says. He loved it, plain and simple.

After the first game of his junior year of high school, Kline committed to the Bears — and spent the next year and a half recruiting others on Cal’s behalf. He even casually influenced Patrick Worstell, a close friend since first grade, to pick the school.

Kline was the crown jewel of Jeff Tedford’s 2012 Signing Day class, and he literally could not wait to come to Berkeley. In February 2012, while the rest of his class waffled over last-minute decisions, Kline was already living in the Clark Kerr dorms after graduating from high school early.

At that year’s intra-squad spring game, Cal unveiled Kline. The freshman completed a game-winning two-point-conversion pass to Jackson Bouza in the fourth quarter and solidified his identity as Cal’s next big thing.

“It was so much fun,” he says. “Because you go from high school, and then you’re finally playing college football.”

During his redshirt year in 2012, he never grew impatient. Cal was the dream, after all. He was playing under a coach he had admired throughout his career in a stadium he’d known since childhood.

“I was thankful even to have the cleats on,” Kline says. “It’s so easy for a freshman to get hated, and I did not want to go down that road. I just did what they told me to do, and I was thankful every moment.”

Observing from the sideline would pay off. Everyone — fans, reporters, even Kline’s parents — figured he would nab the starting role the following season.

In a prelude to the football season, the major headline centered around a three-way battle for the top signal-calling spot. Kline, junior Austin Hinder and newcomer Jared Goff spent the offseason locked in a fierce and hyped-up competition.

“It was so much fun, spring and fall,” Kline says. “Because every day you got reps, and every day you competed.”

On Aug. 16, the team announced its answer to the long-fraught question: True freshman Goff would lead the Cal football team. At the end of practice that day, media swarmed head coach Sonny Dykes, Goff and Kline. Kline kept repeating one phrase: “It’s not over.”

There was neither threat nor resentment behind his words, only sincerity. He was disappointed. He knew he was a good quarterback. He would obviously support Goff.

“Heck, I wanted to,” he says of starting. “That was the goal.”

It still is for Kline, who took the situation with surprising perspective. Football “takes up 90 percent of your life,” according to Kline, and that final 10 percent around the edge is crucial.

He defines himself largely outside the sport — through his faith, through the punk rock music he plays on his Les Paul guitar. His interests are so varied that his mother calls him a “Renaissance kid.” Not your typical jock.

His life was far from over. His career wasn’t even over.

“I want to be here,” he said after the Oregon State game on Oct. 19. “I committed here for a reason.”

So he reworked his role on the team. He took on the backup spot with pride, molding it to fit his personality.

“He’s handled it fantastic,” Worstell says. “He’s just trying to do the best he can and to help out his team the best he can.”

For now, that means donning a headset. Kline is one of four people who can talk to Goff during live action, and he embraces the position. Although Dykes has tabbed Goff as Cal’s “long-term solution,” the head coach still concedes that each week every starting position is up in the air. Kline stays competitive every day, knowing he can’t control the coaches’ decisions.

“I can only do what I can control, and that’s give 100 percent effort every single day,” Kline says. “And having as much energy and being as committed to the team as I possibly can.”

He can no longer assume the same vocal leadership that a starting position naturally entails, so he works hard to bond with teammates — to listen, to be a voice of encouragement.

He has always been a leader, never a follower, according to his mother. A depth chart couldn’t change that.

“You have to change your leadership role around a little bit,” he says. “And it’s been really good to learn it, because my whole life I’ve been the starter.”

There is a tension inherent to his role: He usually enters a game when something goes wrong. But the circumstances don’t dampen his outlook. When the opportunity arises, he seizes and savors it.

A major quarterback substitution has happened twice this season: against Oregon and against Oregon State, both blowout losses. In each outing, Kline posted respectable numbers.

“The good thing is, he’s gotten the opportunity to play,” says offensive coordinator Tony Franklin. “He’s shown why it was such a tough battle.”

When coaches let Kline know he will sub in, he has only a few minutes to warm up before entering the game in media res.

The emotion that builds with “Black Thumbnail” finds its outlet as he takes his first snap.