The Vikings had not selected a defensive back in the first round of the NFL draft in nearly two decades until they traded up to grab Notre Dame's Harrison Smith with the 29th overall pick Thursday night.

Smith, in fact, became only the third defensive back -- and second safety -- taken by the Vikings in the first round in their draft history, joining Joey Browner (1983) and Dewayne Washington (1994).

The historical significance coupled with paper-thin depth and abysmal production from that position last season removes any notion that Smith can ease into things as a rookie, which is fine with him. The Vikings don't need to publicly anoint Smith a starter to underscore what's expected of him. A quick scan of the roster provides enough clarity.

"Who doesn't want to start?" Smith asked, rhetorically. "Why would you play the game if you don't have that competitive fire? It's an honor for them to think enough of me to spend such a high pick on me. I want to back that up and make them right."

Besides, that's not pressure. That's fun to Smith. Pressure is living a few miles from a football-crazed campus in SEC country and turning down the hometown school in order to play elsewhere. Smith, a Knoxville native and star athlete, experienced that emotional tug-of-war as a high school senior when he spurned the Tennessee Vols in favor of Notre Dame.

"It was the hardest decision I faced in my life," Smith said.

Not that he found much support around town. Fortunately, nobody asked his family to pack up and leave with him, at least not directly.

"We thought they might," said his mother, Susan, who is able to laugh about it now. "They were not happy that he was leaving. I think they were shocked he didn't go there."

Smith has always marched to his own beat. A product of Catholic-school education with rigid dress codes, he let his hair down -- literally -- at Notre Dame. He grew his hair long and even went to a Halloween party dressed as Shaggy.

"My buddy was Scooby-Doo," he said.

There's no mystery to solve in his new role. He's being counted on to help improve a substandard secondary that failed by nearly every conceivable measure last season. The safe bet right now is that Smith starts alongside Mistral Raymond or Jamarca Sanford to open the season, which probably won't strike fear in the hearts of opponents, but then again, what's the alternative?

The Vikings desperately need playmakers in the secondary. Someone who can change momentum, make a big hit or -- as crazy as this sounds -- occasionally intercept a pass. That would be nice to see.

Smith showed that ability at different times in college. He had seven interceptions as a junior but came up empty in that stat column last season.

"I dropped a couple balls I should have had," he said.

The Vikings seemingly led the league in that category in recent years. Too many potential interceptions ricocheted off their pads, hands or facemasks. They hope Smith can change that.

Smith began his college career as a strongside linebacker before moving to safety, so he's comfortable playing close to the line. Vikings coach Leslie Frazier also likes Smith's cover skills in the middle of the field.

The Vikings privately coveted Smith after working with him at the Senior Bowl and weren't willing to risk losing him by waiting to see if he dropped to them in the second round.

They like his versatility, were impressed by his leadership and felt he'd be a perfect fit for their defense and locker room. Maybe they didn't need to trade up, but their situation at safety was too dire and the dropoff at that position after Smith too steep for them to take a chance.

"The fact he can play in the box or play deep; it's hard to find those guys," Frazier said. "That's why the safety position is not as deep, because it's hard to find guys who are able to do both. He has the ability to be effective in both areas."

Smith's ability to cover the new wave of specialized tight ends will be his toughest transition. It's become fashionable for teams to employ big, agile tight ends primarily as receivers to create mismatches. They are too fast for linebackers, too big for safeties.

"They can do it all," Smith said. "Can you come down and cover those guys and make them less of a threat?"

Good question. We'll find out soon enough.

Chip Scoggins • ascoggins@startribune.com