EAGAN, Minn. -- Mackensie Alexander's growth as an NFL player delves beyond honing the physical skill set needed to play one of the most difficult positions on defense.

The Minnesota Vikings cornerback's maturation features a heavy dose of self-actualization. It involves learning how to get out of his own way. It's about coming to terms with why he struggled with what the Vikings asked of him during his first two seasons. And it started with a long, hard look in the mirror.

"It's about growing up, sometimes," Alexander said. "You got to grow up and do your job and do what's asked of you."

Entering his third season, Alexander has his sights set on becoming a critical part of the league's No. 1 defense. No longer rebelling against playing nickel corner, Alexander's change in mindset has afforded him a fresh start at embracing the job he hopes to win in 2018.

"I want to compete and just be the best Mackensie I can be for my team each and every day, and I wasn't that in the past, fighting it because I didn't want to do it," he said. "You're a young guy coming in, you've got expectations, but coaches have plans for you. When you see their plans, you want to be a part of this defense. And that's what I want to be a part of. I'm past the past. I'm past the college stuff. I had a great college career. It's Year 3 and it's time for the best nickel in the game."

But it wasn't always like that for Alexander. In his mind, he was a first-round cornerback -- one of the best in the draft -- and he was being asked to play nickel corner. He was better than that and had the college résumé to prove it.

Alexander quickly made his mark at Clemson as one of the best outside corners in the country. After redshirting in 2013 with a groin injury, Alexander thrived as a freshman and sophomore, allowing a mere 29.6 completion percentage on passes thrown in his direction and no touchdowns. Regularly tasked with covering his opponent's No. 1 receiver, the 5-foot-10 corner had no qualms about taking big, physical receivers to task with his elite coverage skills.

Regarded as one of the best cornerbacks in his class, Alexander was selected by the Vikings in the second round of the 2016 draft. His skill set drew intrigue. He didn't have the prototypical size of a top-end NFL corner, but his strengths as a press-man defender and instincts outweighed his stats. It mattered very little to the Vikings that Alexander left college without an interception and having defended only 10 passes.

What Minnesota saw in evaluating Alexander's fit in the defense is a player whose tools could make him a good fit.

"His attitude was really good as far as competition," Minnesota defensive backs coach Jerry Gray said. "It's just getting him to understand where you fit for us. I don't worry about interceptions; I worry about how close you can get and what's your attitude about covering."

The transition from college to the NFL is often difficult for cornerbacks. In Alexander's case, being asked to move inside felt completely foreign, but his early struggles aren't tied to the nickel corner position alone. The Vikings hope this season that Alexander's trajectory will mirror those of Xavier Rhodes and Trae Waynes in their third seasons, when things finally started to click.

But what's being asked of Alexander is different. The position he's expected to win comes with far more challenges.

A nickel corner has to concern himself with everything around him, from what's going on with the defensive line, to where the linebackers are and how the outside corners and safeties are going to adjust based on how a receiver lines up and where he breaks on his route. He doesn't have the sideline as a boundary and has to be comfortable playing in space. It's a position that relies more on reactive quickness versus the straight-line speed an outside corner needs to track a wideout.

"It's a different skill set inside because you have a lot of communication going on with the 'backers as far as route progressions, as far as run fits," defensive coordinator George Edwards said. "There is a lot of newness when you take a guy and move him from outside to inside. Especially with all the formation variations we get from offenses in this league. [There are] a lot of things that are happening and it's the first time through. You are really out of your comfort zone."

With so many layers to the position, it's no surprise the nickel takes most players several years to master. According to ESPN Stats & Information, over the past five years, only two rookies (the Falcons' Brian Poole and the Chargers' Desmond King) played at least 500 snaps as a slot cornerback. That number grew to eight when including players in their second and third year. The data shows it took most slot corners until Year 4 to fully grasp the position. Among the same parameters, 24 players in their fourth year played 500 or more snaps in the slot.

Minnesota brought in Alexander to learn under Captain Munnerlyn as a rookie. Munnerlyn played 61.45 percent of nickel corner snaps in 2016, then moved on in free agency. Sights were set on Alexander winning the job last season. While there were some bright spots during training camp, Alexander eventually lost out to Terence Newman.

The 39-year-old Newman played the third-most snaps among all Vikings defensive backs with 555, with the majority in the slot. Alexander saw his playing time increase from his rookie season, playing 32.46 percent of defensive snaps in 2017, but his second year was filled with ups and downs. That included the high of his first interception, which came in Washington against his new quarterback Kirk Cousins, to a low of allowing a critical fourth-down pass from Drew Brees to Willie Snead in the divisional playoffs that might have become a bigger talking point had Case Keenum and Stefon Diggs not bailed the Vikings out with the Minneapolis Miracle.

Given how often teams turn to their nickel package, the nickel corner is essentially a starting position in today's NFL. Newman's vast experience was readily available for Alexander to tap into. When he finally chose to heed Newman's advice, Alexander felt a deep sense of pride.

"You realize, 'Dang, this guy played 16 years in the league and I only played five' or 'If I would have knew back then ...'" Alexander said. "I definitely don't want to be one of those guys. I want to be like, 'Yeah, I came up under T-Newman' and not have an ego about it, being like I came up under one of the best to do it."

Newman, who often stays after practice to work with younger cornerbacks, notices a change in Alexander's mindset.

"I think a lot of young guys come in and they're the man on campus," Newman said. "You get around a situation where you've got way more people, so it's hard to get complete one-on-one time. I think he just understood he's got to do extra stuff. Attitude is completely different. He's super eager and super hungry to get better and to learn."

The Vikings, who used their first-round pick in April on another cornerback in Mike Hughes, don't have any qualms about their depth at the position. It's not as if they're tied to Alexander's winning the job in order to retain their status among the league's top passing defenses. But if training camp wears on and the nickel corner battle shifts to a 40-year-old veteran and a rookie pushing for the job, Alexander might not have another opportunity.

Alexander, who set a goal to become a top-five nickel corner this season, is no longer playing the defense the way he did a year ago. Instead, he's using technique to adjust to who he's playing in the defense. His versatility will help make his job easier if he moves back outside in the future, and that only adds to his value.

"Most guys can't do that transition and go inside and outside," Alexander said. "I'm loving it. I'm embracing the job, I showed just a little bit, a splash of things I can do last year and the plays that I've made. Year 3 is coming up and I'm ready."