Cardinals defensive tackle Robert Nkemdiche works during a recent OTA.

There is no hesitation from veteran Frostee Rucker when the name Robert Nkemdiche comes up.

"He's changed," Rucker says. "For the good. He's changed."

Few have been around the Cardinals' training facility more often than Nkemdiche,  the team's 2016 No. 1 pick, who began showing up to work out by himself many days not soon after the season ended. He's among the defensive linemen to get in extra technique and conditioning after the coaches head inside following that day's OTA. He is reluctant to talk much about where he stands heading into Year Two, because he knows only his play is going to convince anyone of what he can be.

"It's staying on the path of what I am doing, staying focused, trying to be as pinpoint perfect, not being on the (mental error) sheet and not making minute mistakes," Nkemdiche said. "Keep working hard, take it day by day."

He has believers in those who see him every day.

"People want football to be microwavable," defensive line coach Brentson Buckner said. "Football is not microwavable, especially on the defensive line.

"I've been happy with him," Buckner added. "I never got down on him. I didn't expect him to come in and do all that dominating, because I knew the position. It takes time. It takes some guys even longer. He is starting to come around. He's in great shape. He's fully back from the ankle. You see the natural ability take over. Now it's all about Robert."

Nkemdiche played in just five games as a rookie, with three tackles. It would have been a shock, except the Cardinals had just gone through the previous season without their No. 1 pick – tackle D.J. Humphries – active for even one game. Nkemdiche's season was disappointing, but it wasn't even on the list of the reasons the Cards struggled to a 7-8-1 record.

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Coach Bruce Arians noted a couple of times that Nkemdiche – who didn't turn 22 until the season had started – had to first grasp what it was like to play in the NFL and what that meant. Buckner said it took Nkemdiche a moment – or many moments – to adjust to not being a superstar from the time he arrived. In high school and when he got to college at Ole Miss, he was dominant just by showing up.

"They're young kids," Rucker said. "They don't know how a locker room is, they don't know how to be professional, they don't know how to study, that guys are counting on them and it's not just about you. This spring, I've seen Robert change his whole demeanor towards work. That's all you ask from a guy."

Nkemdiche said he just wants to take his rookie season as a learning experience, saying that he never let himself get frustrated.

"Frustrated means that you're not aware of the lesson you are being taught," Nkemdiche said. "I wasn't

frustrated. Of course I think things could have gone differently, but they didn't. That's what this world set up for me. Last year wasn't my year to be ready. So I took a step back, learned from it, and got a better understanding about how to be a professional football player."

Buckner wants Nkemdiche to ignore the expectations. While Arians noted he hoped Nkemdiche could replace the departed Calais Campbell, Buckner said he wants to avoid anyone having that burden. His message to Nkemdiche was simple – if it isn't himself or Arians or defensive coordinator James Bettcher saying it, the rest "is just elevator music."

"I told him, 'Robert, you don't have to be anything but the best Robert Nkemdiche you can be, and I'm cool with that,' " Buckner said. "If you give me 100 percent of Robert Nkemdiche – not what people expect you to be – give me what you can give me, your honest 100 percent, I'm going to be cool."

To this notion Nkemdiche nods his head. After last season, the chance to progress so that coaches deliver public praise – which Arians did start to do in December -- is a goal, validating his steps forward.

There's only so much that can be accomplished in May. Another little bit will come in training camp. Where Nkemdiche stands in September for the opener in Detroit will be telling.

But right now, it seems Nkemdiche has morphed over the months.

"I'm very proud of him," Rucker said. "I'm not going to tell him to his face yet, but toward the end of training camp, I'll probably tell him. Because I know he's trying to become a dominant player. He's trying to step up and make his name and make a role for himself, and that's all you can ask of him."