STANFORD — The time every Stanford supporter has dreaded has finally arrived.

The Andrew Luck Era is over.

As one of the most promising and productive periods in the program’s history ends, the real challenge for first-year head coach David Shaw begins this offseason: Keeping the Cardinal among the nation’s elite.

Even without Luck.

“Since he’s officially not completely mine anymore, I will completely go over the top and say that he’s a Hall of Fame college football player,” Shaw said. “They come around every 20 years or so. He hates to hear that, but it is the doggone truth.”

Here’s another truth: Stanford faces a radical rebuilding project in Luck’s wake.

The No. 4 Cardinal’s 41-38 overtime loss to third-ranked Oklahoma State in the Fiesta Bowl on Monday night will forever mark the finale of Luck’s brilliant college career. In the years to come, the date also will symbolize either the start of Stanford’s dip back to mediocrity or the dawn of a new day of dominance on The Farm.

After all, the exodus goes well beyond the two-time Heisman Trophy runner-up.

Offensive linemen Jonathan Martin and David DeCastro are set to join Luck as projected first-round picks in April’s NFL draft and much of the supporting cast on both sides of the ball is graduating, including top tight end Coby Fleener and starting safeties Michael Thomas and Delano Howell. Junior linebacker Chase Thomas is still deciding whether to return.

While all had roles in Stanford’s turnaround, Luck had the most lasting impact.

A losing program when Luck arrived, the Cardinal (11-2) have been to consecutive BCS bowls the past two seasons and Luck has cemented his place among Stanford’s greats. He leaves as the unanimous choice for the No. 1 pick, which the Indianapolis Colts hold, and at the head of a Stanford class that raised expectations for every team that follows.

“They came in with the mindset that they are going to make a splash here,” Shaw said. “That they were going to show the nation that you can be a high academic institution and go to BCS bowl games and make it happen, that there are young men out there that are looking for what Stanford University has to offer, which is the best of both worlds.

“We are not going to shy away from that. That’s our mission. And these guys, Andrew in particular, were at the forefront of that.”

Luck’s legacy is unmatched in Stanford’s history.

He owns almost every major school passing record, including most touchdown passes in a single season and career. And Luck will be lauded on campus for his unconventional decision to return after last season, risking millions to finish his degree in architectural design and take shots at a Heisman Trophy, Pac-12 title and national championship.

He fell short of most of those goals.

Instead, he’s right back where he was a year ago: ready to be the NFL’s top pick, only with another year of experience and just a few classes away from earning his degree.

“Yes, it was worth it,” Luck said. “Not to say I enjoyed every moment, because I didn’t. But I would never regret it. I felt I grew a lot as a person, as a player. Just in life, I learned a lot. Got a chance to be around guys like Chase and Delano. I think we’ve forged unbelievable friendships and had a chance to play a great college football game. Definitely worth it.”

Finding his replacement is a process not expected to be completed until the fall.

Sophomore Brett Nottingham beat out juniors Josh Nunes and Robbie Picazo for the backup job this season, and Nottingham showed remarkable efficiency —albeit in mop-up duty — in limited action behind Luck. Redshirts Kevin Hogan and Evan Crower will also compete for the starting job beginning in the spring.

The real challenge long-term is Shaw’s recruiting ability.

Former coach Jim Harbaugh, who left after last season’s Orange Bowl victory over Virginia Tech to carry the San Francisco 49ers to the playoffs for the first time in nine years, built Stanford back from irrelevancy to college football heavyweight in only four years. He recruited a specific type of athlete — honing in on talented players who care equally about academics — and Shaw has tried to follow suit.

Recruiting has been solid so far under the former Stanford wide receiver, and many project Stanford to turn in another top-20 recruiting class by signing day in February — or at least come close. Whether the program can match its recent success in the post-Luck era is uncertain.

“We’ve been pretty good in the past, and we’ve been not pretty good in the past,” Stanford athletic director Bob Bowlsby said recently. “Aspirationally, it’s fun to be where we were the last two years, but I’d be naive to think it was going to be like this every year. But I’d like to take the peaks and valleys out of it.”