STANFORD – Stanford has started the post-Andrew Luck era with an unproven quarterback who possesses a can-do spirit.

When relatively unknown Josh Nunes steps into the limelight Saturday at Stanford Stadium to face second-ranked USC in a Pacific-12 Conference showdown, he will be starting just his third game since 2008.

What, him worry?

"It would be a lot more nerve-wracking if I were iffy on certain concepts," said Nunes.

Over the past three years, Nunes served as an apprentice to Luck, the NFL's No. 1 draft pick and a two-time Heisman Trophy runner-up. The thankless hours as an understudy allowed Nunes, 22, to move into the starting role because of his command of the playbook.

After two games, Nunes has thrown for 400 yards and four touchdowns, completing 32 of 56 passes. He had one completion in college – all of seven yards – before winning the starting job nine days before the season opener.

By contrast, USC's Matt Barkley is a Heisman Trophy front-runner and potential No. 1 draft pick who threw for six touchdowns against Syracuse last weekend.

"The worst thing he can try to do is try to compete with Matt Barkley," Stanford coach David Shaw said. "We're not in that business. We're not playing that game. We're going to play our style of football."

Even during Luck's reign, Cardinal coaches didn't measure their quarterback on numerical performance alone. The infinitely complicated playbook requires so much more from a signal-caller than simply firing missiles downfield.

Nunes, a management, science and engineering major who needs only four classes to graduate, left nothing to chance this summer when competing against Brett Nottingham and Kevin Hogan for the starting job. He turned down a coveted internship with semiconductor firm Maxim Integrated of San Jose to train and devour game film.

"Maxim was a big deal to him," his father Tim Nunes said. "But he had a responsibility to teammates and school, too. We all know who he is replacing."

Nunes got his first real test using multiple schemes last weekend in a 50-13 victory over Duke.

Shaw liked how the quarterback responded.

"He made some mistakes, but you never see him rattled," Shaw said.

When the coaches changed protection schemes and running plays between series, Nunes told the staff, "I've got it."

"We never had to write things down or change his wristband," Shaw said. "We just had to tell him to change a couple things and he did that."

The sophisticated play calling piques Nunes' intellectual curiosity. Devising plays is what attracted the 6-foot-4, 225-pound athlete to the game in the first place. Then he fell in love with the camaraderie of teammates united by a common cause.

"It is something you can't get anywhere else," said Nunes, who plans to attend graduate school next year to continue studying entrepreneurship.

Nunes seemed destined to pitch in the major leagues. He had a 90-mph fastball and once struck out all 18 batters in a Little League game. Tim Nunes discouraged Josh and his younger brother, Justin, from playing tackle football to prevent injuries from spoiling promising baseball careers.

But Josh excelled as a quarterback at Upland High School in San Bernardino, where he had a 4.6 grade-point average, and was a major influence on Justin, now a redshirt quarterback at UC Davis.

Though Nunes fielded recruiting pitches from Florida, Oklahoma and Tennessee, Stanford had an advantage – and not just because it is located in the heart of Silicon Valley, where entrepreneurship is part of the DNA.

His father wasn't thinking about college scholarships when coming home one day with a Stanford cap for his 8-year-old son.

"It just came to me," Tim Nunes recalled. "I put it on him. 'You belong to Stanford.' "

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