Intercepting the opposing quarterback can be a wonderful, game-altering experience. The Vikings should try it more often.

At 7-9 a year ago, it's safe to say they will need a lot to go right in a lot of different areas to climb past the Lions and Packers in the NFC North. But intercepting Detroit's Matthew Stafford and Green Bay's Aaron Rodgers would be a nice place to start.

Against the Vikings, Stafford has thrown 121 consecutive passes over 15 quarters without an interception. Rodgers, meanwhile, has gone 154 consecutive passes without a pick dating back to Dec. 2, 2012.

Friday, the Vikings got their first look at the rookie class of 2015. The three-day minicamp features 10 draft picks, including two projected defensive starters in first-round cornerback Trae Waynes and second-round middle linebacker Eric Kendricks.

Also signed and on the field with several tryout invitees are 10 undrafted rookies. Record-setting Old Dominion quarterback Taylor Heinicke and three receiver hopefuls are the headliners.

Of these 20 preferred camp attendees, only one is a safety, which, in case you missed it, remains a position of need next to Harrison Smith.

The safety's name is Anthony Harris, who was undrafted out of Virginia. He looks a little thin (6-1, 183 pounds) for a safety and isn't participating because he's only five months removed from major shoulder surgery that likely knocked him from the middle rounds of the draft to college free agency.

In other words, he was easy to overlook. But something that General Manager Rick Spielman said after the draft tells us the Vikings don't view Harris as just another camp body.

When the draft ended and the Vikings came away with none of the 15 safeties selected, Spielman was asked how he felt about the team's safety spot next to Smith. He smiled and said, "I'll let you know when our college free agency comes out."

ESPN draft analyst Todd McShay predicted the Steelers would select Harris in the third round. Three days later, McShay listed Harris as the top undrafted rookie available. The Vikings wouldn't argue.

"He's a very instinctive, very smart, very communicative safety," coach Mike Zimmer said. "I think he plays real hard. I think he has a lot of the traits of the starting safeties in this league."

Harris also has 10 interceptions the past two years. He led the nation with eight as a deep safety in 2013 and had two last year when asked to play close to the line of scrimmage as a strong safety to accommodate the strengths of a true freshman at free safety.

"Interceptions can come more consistently if you spend the time on the mental preparation," Harris said. "I really got comfortable with route recognition, studying tendencies, getting a feel for the quarterback. I would spend at least an hour a day outside of what we did with the coaches just watching film with a paper and a pen looking for advantages."

The Vikings have ranked in the bottom half of the league in defensive interception percentage the past four years. The best ranking by far (19th) came last year under Zimmer even though the noted defensive expert doesn't teach an interception-friendly scheme.

"With our defensive backs, it's about denying your guy the ball," Zimmer said. "I know you go to the Pro Bowl on interceptions. So that's always a hard thing for me teaching our players because everybody wants to go to the Pro Bowl."

Zimmer said more can be done to increase interception totals, but not without the risks that come with playing unsound defense. He teaches tight coverage first and foremost.

For now, Harris is learning the free safety position. In time, he is expected to learn strong safety since the two are so interchangeable in Zimmer's scheme.

A year ago, the Vikings had 13 players on the roster who entered the NFL as undrafted rookies. At strong safety, the preferred starting candidate this year is Antone Exum Jr., a 2014 sixth-round pick who played 16 defensive snaps a year ago. That should tell you that Harris can't be ruled out as a roster survivor and maybe more.

"They brought me in here for their top-30 visit before the draft and I just knew it was the place for me," Harris said. "The relationship with the coaches was the best for me. I'm just a player looking to get better, and everybody knows the reputation Coach Zimmer has with defensive backs. It's Day 1 and I've already picked up things from him standing here. I can't wait to get started."

Mark Craig • mcraig@startribune.com