EAGAN, Minn. -- Anthony Harris' career with the Minnesota Vikings is rooted in the need to be on notice, constantly on call, waiting for his moment to step in should an injury or suspension arise to another starter. That's how the safety first saw the field four years ago, activated off the practice squad during his rookie season to aid a depleted defensive backfield.

But Harris wasn't just relied upon as a fill-in. In his first NFL game against the Arizona Cardinals in December 2015, the then-rookie was tasked with calling the defense from his spot at safety. It was a moment to not only show off his ball-hawking skills, but his ability to orchestrate everything around him.

"And I could see the light bulb really click that everybody was like, 'Hey this guy can play,'" Harris said. "'He's going to be somebody who can go in and make plays for us.'"

Four years in, Harris' role is changing. On Tuesday, the Vikings placed veteran safety Andrew Sendejo on injured reserve after a groin injury he sustained in the first part of the season kept him sidelined since Week 5.

Outside of Pro Bowler Harrison Smith, the outlook for the Vikings' safety position is cloudy. Sendejo, 31, carries a $5.5 million cap hit in 2019. A restructure of his contract feels inevitable if he's going to stay with the Vikings next season. And it still might not be enough to keep his starting job.

Coming off his fourth consecutive start in place of Sendejo, Harris will remain in this role for the rest of the season, according to coach Mike Zimmer. He has been patiently waiting, pining for his opportunity for years. Now that he has it, things may never go back to the way they were before.

Harris entered the NFL in 2015 as an undrafted free agent from the University of Virginia. Injuries at the end of his college career and subsequent shoulder and hand surgeries limited what he could do physically early on in Minnesota, so he saw an opportunity to hone his talents elsewhere.

His aptitude in the meeting room was quickly noticed by coaches.

"He's always taking notes," defensive backs coach Jerry Gray said. "A lot of times the young guys really don't even understand, when a professional's up there talking, and they're telling you something, they may not be talking directly to you but you have to decipher what they're doing, and then this is what I need to get. And I see him doing that.

"To me, he studies, does his job every time the right way. And then when he gets a chance he goes in and plays, and he plays like he should be the starter."

Harris wasn't the starter against the Cardinals in Week 6 but had the impact of one in the third quarter, notching his first career interception against rookie QB Josh Rosen.

It wasn't just the pick itself that impressed coaches. It was the propensity required to make the play.

With Arizona receiver Larry Fitzgerald breaking on an angle route, Harris had to be in the right position to disrupt the trajectory of Rosen's pass. Had he whiffed and Fitzgerald caught it, Fitzgerald would have kept running. It was the same on Harris' first of two interceptions in Chicago, the safety running deep over the middle of the field on the Bears' "all-go special." Once receiver Taylor Gabriel showed signs of bending away from the safety, Harris leapt for the ball.

"I see young guys, they're really apprehensive of going and making plays," Gray said. "They could be in position, but they don't make that play. And to me, I think that's a thing that you've seen him do. I think mentally he knows what to do, physically he knows what to do. Now, do you have enough courage to go make the play?"

Harris is one of many Vikings starters to get his start on special teams. Even this season, the "teamer" only saw the field on punt and kickoff return during the first five weeks and didn't take a defensive snap until Week 6. Even though he's seeing his role expand at safety, it doesn't mean his special teams play will become obsolete.

"For me, it's very rewarding to see those guys that last in the league five, six, seven, eight, nine years and contribute on special teams when they are called upon in certain phases, but still do a great job for us on offense and defense," special teams coordinator Mike Priefer said.

Harris is again a restricted free agent in 2019, and it's hard to imagine the Vikings won't place a tender on him. While he wasn't one of the 15 safeties chosen in the 2015 draft, he has outperformed most all of them this season and is ranked No. 2 among all safeties by Pro Football Focus.

He already has done what's needed to remain in Sendejo's place for the rest of the season. Beyond that, Minnesota may not have to look far for its next starting safety.

"I think at the end of the year, we'll sit back and evaluate and say, ‘Hey look, what's going to be good for us? What's going to be best for us as a Minnesota Vikings defense?'" Gray said. "And it's going to be a big discussion, because now we've had another guy step up.

"To me, the NFL is always revolving and evolving to guys. And we're always looking for guys who can take a role and be better at that role. And at the end of the year, we'll have a tough discussion, I'm pretty sure."