Stanford quarterback Andrew Luck is presumed to be the No. 1 pick in the next NFL draft. On Saturday, the visiting Washington Huskies will face Luck.

Opposing coaches call him the best college quarterback they’ve ever seen.

Draft analysts call him the most NFL-ready quarterback in more than a decade.

The media have tabbed him the favorite to win the Heisman Trophy this season.

David DeCastro, though, simply calls Stanford quarterback Andrew Luck a friend and roommate.

“He’s just your average guy,” insists DeCastro, a former Bellevue High offensive lineman who was Luck’s roommate during training camp and now shares an apartment-style dorm with the Stanford quarterback during the season.

“He’s just a normal person. I think everyone makes him seem like something else. But he’s really not. He’s just Andrew.”

Maybe so.

But Luck, who will lead Stanford against the visiting Washington Huskies in a 5 p.m. game Saturday, is regarded by many as a once-in-a-generation quarterback, a rare blend of physical talent and mental acuity who — along with former coach Jim Harbaugh — has been responsible for the Cardinal’s rise.

Stanford has won 14 straight games, the longest winning streak in the country, and has won its six games this year by an average score of 45-11.

“Oh, he’s a pretty good player,” UW coach Steve Sarkisian deadpanned earlier this week. “I think what Andrew has, and I’ve appreciated this about him watching him, the physical tools; I mean, he’s 6-4, maybe more now, 245 pounds. He can run, he’s got great arm strength, he’s got great anticipation.”

But as much as coaches and draft analysts marvel at Luck’s physical skills, they say what really sets him apart is the mental aspect of his game — which might make sense for a player soon to receive a degree in architectural design from Stanford.

“They don’t run a bad play,” Sarkisian said. “And that’s because of him. That’s because of his ability to prepare mentally. And so I just haven’t seen him make a bunch of poor throws or throw into coverage or make a bad play. And that’s the beauty of him. For a kid in college to be doing all that stuff is pretty impressive.”

Indeed, Luck has been given the rare responsibility of calling plays for the Cardinal at times this season, given what Sarkisian says is an almost unprecedented say in what the team runs.

Rob Rang, senior draft analyst for NFLDraftScout.com, said Luck was universally regarded as the best player in college football heading into the season and “all he’s done is improve.”

Rang said Luck is “my highest-rated prospect in 12 years of scouting. … Physically speaking, he’s a rare prospect. … What makes him such an incredible talent, however, is his mental ability. Luck is the most intelligent quarterback I’ve scouted. I’ve spoken to veteran NFL scouts who rate his mental aptitude higher than Peyton Manning when he left Tennessee or any quarterback since. Luck reads defenses at the line of scrimmage and makes the correct adjustments, often calling audibles to running plays rather than just calling his own number, as many other quarterbacks would do. Even more impressive, Luck shows the ability to make adjustments after the snap, often hurting defenses who challenge him with surprise blitzes and coverages.”

So what’s a defense to do?

Washington defensive coordinator Nick Holt says, “There are some things we can do. The problem is, if we do too much we’ll kind of nail ourselves in the ground and we won’t play as hard as we need to, so we’ve got to be careful with that. So we’ve just got to do a nice job in our base stuff and get a lot of guys to the football and get some turnovers and not give up any big plays over our heads.”

That Luck was such a sure bet to be taken No. 1 in the NFL draft made it somewhat of a surprise that he decided to return for another season. He is a fourth-year junior after having redshirted as a freshman in 2008.

Luck, though, said he wanted to earn his degree in architectural design and enjoy one more year of college. (He’s the son of former NFL quarterback Oliver Luck, currently the athletic director at West Virginia.)

He’s also said he felt a desire to finish what he started with the Class of 2008 that helped Harbaugh turn Stanford around, even though Harbaugh is gone, coaching the San Francisco 49ers. That group was Harbaugh’s first full class at Stanford after taking over for Walt Harris following the 2006 season. Luck, a Houston native, also considered Oklahoma State, Purdue and Virginia.

Stanford is helping Luck’s desire to have as normal of a college existence as possible this fall by — in the words of coach David Shaw — “shielding” him from the media. While he did a number of interviews early in the year, these days he usually meets with the local media only once a week and after games.

“I don’t think I’m treating (this season) any different,” he said. “It’s just another opportunity to play football.”

And if the accolades ever get too big, he’s got DeCastro to keep him in line.

“He’s nothing special,” DeCastro insisted. “Just a good guy to hang out with.”

Bob Condotta: 206-515-5699 or bcondotta@seattletimes.com