STANFORD, Calif. — The text messages from friends and family in the Los Angeles area pile up in Jonathan Martin's phone with the same question every time the latest NFL draft projections are released.

"They definitely text me, 'Who's this Kalil guy?'" he said.

The Martins will find out firsthand this week.

Southern California's Matt Kalil and Stanford's Martin are the top left tackles in the nation and expected to be among the first 10 picks in April's draft. They also protect two of college football's best quarterbacks, Stanford's Andrew Luck and USC's Matt Barkley, making the position all the more important on their teams.

The offensive linemen bring a scintillating subplot to Saturday night's matchup at the Coliseum between fourth-ranked Stanford and No. 20 Southern California. The national stage is a chance to showcase their talents together and create some separation on draft boards everywhere.

Call it the Battle of the Blind Sides.

"They are Pro Bowl-quality left tackles," said draft analyst Gil Brandt, the former vice president of player personnel for the Dallas Cowboys. "Kalil probably has the edge because of his versatility and special teams abilities, but both guys are pretty sure bets."

Left tackle has been one of the most important positions on the field since pass-rushing defenders figured out decades ago that the best way to the quarterback is to come from the side he can't see.

The 2009 motion picture "The Blind Side," which chronicled Baltimore Ravens left tackle Michael Oher's journey from homelessness to first-round pick, made the position a household name. The job of a left tackle is often to block the defense's best pass-rusher, protect a right-handed quarterback's back side and set the edge blocking on running plays.

"It's the premier position on the offensive line, which is why every year when you look at the NFL salaries, the left tackles are paid more than everybody else on the line," Stanford coach David Shaw said. "For the head coach and the quarterback, it helps them sleep at night."

USC and Stanford must sleep well then.

The 6-foot-7, 295-pound Kalil has led a young Trojans (6-1, 3-1) offensive line that has only allowed four sacks on Barkley all season. He is considered the more polished of the two at the moment and adds a special teams spice; draft analysts ESPN's Mel Kiper Jr. and Scouts Inc.'s Todd McShay project the tackle could be drafted as high as No. 2 — behind Luck, of course — if he forgoes his senior season.

Kalil has blocked more than just defenders, too.

In one of the biggest plays of USC's season, the tackle moved to the other side of the ball and swatted Utah's 41-yard field goal attempt on the final play to secure a victory, one of five blocked kicks he has this year.

"If we had four more of him up there, we'd have no issues," USC coach Lane Kiffin said. "We'd be scoring a million points."

Kalil's counterpart is no slouch, either.

Martin, a 6-foot-6, 304-pounder whom Stanford players and coaches call "Moose," starred in high school at Harvard-Westlake School in North Hollywood, Calif. The son of Harvard graduates, he verbally committed to UCLA until he qualified academically at Stanford and took what he considered the best of both worlds.

The pair attended the same football camps in high school but they only know each other through what they've read online or watched on television. Maybe even sneaking a peek or two at draft projections.

"It's something that's hard to ignore," Martin said.

Martin's parents, Gus and Jane, will make the short drive to the Coliseum with his cousins. He also said he knows about "100 people" who attend USC or are associated with the university.

Football runs deep in the Kalil family, too.

Kalil's brother, Ryan, is the starting center for the Carolina Panthers and a former Trojans standout. Their father, Frank, also played with the Buffalo Bills.

While Martin and Kalil have never truly met, each shares an appreciation for the other's job.

"He has a great responsibility protecting a quarterback like Luck, particularly a guy who likes to run out of the pocket like he does," Kalil said. "These two teams have two of the greatest quarterbacks in college football with me protecting Matt, so we both have a lot of responsibility out there. That's what you want as a left tackle."

For teams with top quarterbacks, Stanford and USC rely heavily on the anchor of their offensive lines.

The Trojans shoved the Irish around last weekend, pounding out 219 yards rushing in a 31-17 victory at Notre Dame. Guided by Martin on the left edge, Stanford set a school record with 446 yards rushing last Saturday in a 65-21 whipping of previously No. 22 Washington.

Luck has only been sacked twice all season — neither coming from Martin's defender.

Stanford's offensive lineman set a goal this season of not allowing any hard hits on Luck, especially after he turned down the chance to be the NFL's top pick last April. While Luck has a $5 million NCAA insurance policy and private insurance, Martin's job is to make sure the quarterback never needs to cash them in.

Knowing one blow could derail a career, it's easy to see why the blind-side blocker is a quarterback's best friend.

"You don't want to be constantly looking over your shoulder to know what's going on over there or worrying about that at all," Luck said. "I think Moose has this level of trust and confidence in him from me.

"I mean, there's a movie about that position," Luck added. "How many other positions have movies about it?"

AP Sports Writer Greg Beacham in Los Angeles contributed to this story.

Antonio Gonzalez can be reached at: www.twitter.com/agonzalezAP