MANKATO – Vikings tackle Matt Kalil hardly hears a peep from rookie guard David Yankey.

"He's a quiet guy," Kalil said.

You won't hear Yankey say much. You won't catch him joking around at practice. He won't clog your Twitter timeline with 20 tweets a day.

For a rookie, that's not a bad thing. Yankey is going through the process of breaking out of his shell and adapting to a new locker room, like he did at Stanford. The same could be said on the field as well, where Yankey hopes to find a role on a veteran-led Vikings offensive line.

Yankey hasn't received first-team reps at left guard during training camp, and that won't be in Vikings coach Mike Zimmer's future plans. Yankey is expected to initially back up Charlie Johnson, who has started at left guard for the Vikings over the past three seasons.

"He's unquestionably the first-team guard," said Yankey, who continued to receive second-team reps in Saturday night's practice. "I'm just learning from him as much as possible. He's a great player, very underrated, really technical; one of the oldest O-linemen and a lot of respect for him."

While Yankey, listed at 6-6 and 315 pounds, already possess a bigger frame than Johnson, 6-4 and 305, Yankey missed most of Vikings' organized team activities because of an NFL rule that barred a draft pick from participating in OTAs until after he completes his finals. Stanford operates on a quarter system and its spring finals are in mid-June.

Yankey caught a red-eye flight once he completed his finals to participate in the final three OTA sessions, but he missed a considerable amount of time learning technique, including improving his pad level, hands and feet. Yankey said he must specifically improve his body position and avoid leaning on defenders.

"That doesn't mean he won't get there because he's a smart kid, but he's working real hard on his techniques and his sets," Zimmer said. "He's not making many mental errors as far as who to block and things like that. He's got to do a better job in the technical part of the game of what we're teaching. That may take a little time."

Yankey's biggest strength out of college is his ability as a pulling guard, where he shuffles around the tackle to be a lead blocker on runs. Yankey served as a pull guard often at Stanford, where he became the eighth unanimous All-America pick in school history last year.

"You're almost thinking like a running back," Yankey said. "You've got to see where the hole is and clear that out. And if there's not a hole, then make one."

His athleticism stems from a background that includes baseball and basketball, along with football, in middle school. Yankey started playing football in seventh grade and focused strictly on it at Centennial High in Rosewell, Ga.

He moved to Georgia when he was 8, though he was born in Sydney, Australia, to a Ghanaian father, David Sr., and a Czechoslovakian mother, Darina. Yankey's father died in September from cardiac arrest.

Yankey's past gives him a different perspective on how to interact in a locker room filled with unique personalities. And it's perhaps why, wisely, he's been a silent rookie so far.

"Everyone brings a different background with them," Yankey said. "Everyone has a different history, different legacy, different ethnicity that they bring. That's the cool thing about a locker room. You get all those things mixing together."

Yankey, 22, will be in the team's future plans on offense once he grasps the techniques he needs. Whether that'll be at the end of the season or next year depends on how Johnson performs and Yankey's progress, but the fifth-round pick will get an opportunity to ease into a starting spot — the same way Yankey's slowly breaking out of his shell with his peers.

"[He's] working hard," said Kalil, who went to college rival Southern California. "I respect the heck out of Stanford and the offensive linemen that they produce. I'm excited to see what he brings."