Cardinals defensive tackle Robert Nkemdiche is playing better this season and is hoping to cement a key role on defense.

There was a great deal of hand-wringing in the first few weeks of free agency when one defensive starter after another departed the Cardinals.

By the time the dust settled, five of them– defensive tackle Calais Campbell, safety Tony Jefferson, cornerback Marcus Cooper, safety D.J. Swearinger and linebacker Kevin Minter -- were gone from a group that finished second in total defense in 2016.

While General Manager Steve Keim signed linebacker Karlos Dansby and safety Antoine Bethea to help cushion the blow, the losses were still significant. The question among critics wasn't if the defense would dip in 2017, but how much.

"We lost a lot of great players," nose tackle Corey Peters said. "And that's good for them. They got opportunities to go and make some money, and as a player and a friend, I like to see people maximizing their potential and get the opportunities they deserve. But as far as we go, we were just focused on the guys that were here."

The potential repercussions from such significant upheaval cannot be discounted, but there is also an alternate conclusion to consider: the 2017 Cardinals defense could again be among the NFL's best.

While Campbell is gone, the team returns a pair of premium pass-rushers in Chandler Jones and Markus Golden, who had more combined sacks (23½) than any other duo in the NFL. The Cardinals also have Patrick Peterson, an elite cornerback, and a healthy Tyrann Mathieu, a Defensive Player of the Year candidate last time he was unshackled.

In the end, the unit's success could hinge greatly on three things: the return to form of Mathieu and money linebacker Deone Bucannon (who is still recovering from offseason ankle surgery); the play of the starting cornerback opposite Peterson; and the progress of defensive tackle Robert Nkemdiche, safety Budda Baker and inside linebacker Haason Reddick.

The early signs are encouraging, based off coach Bruce Arians' press conference on Saturday.

Mathieu was highlighted for his play earlier that day in practice, as he returned an interception for a touchdown to continue a dominant training camp. Bucannon was deemed on schedule in his rehabilitation from offseason ankle surgery, which would have him ready for the season opener on Sept. 10 against the Lions.

All three youngsters were praised by Arians for their debuts in the Hall of Fame Game. Reddick didn't make any mental mistakes as he pivots to a new position, while Baker played so well that Arians wondered aloud if the second-round pick would be pushing for a starting spot already had he not missed offseason work.

Nkemdiche's ability to dominate on the interior of the defensive line is critical, and after a rookie season wracked by a bad ankle sprain and immaturity concerns, he is starting to tap into the potential that made him a first-round pick.

The criticism that flowed often from Arians in 2016 has turned into praise. While Nkemdiche understood Arians' motive last season, he's glad to be on the flip-side now.

"Although you have to have self-confidence, it helps when you have other people around you that believe in you," Nkemdiche said. "Especially people that are your family. It makes a difference. You're just more loose. When you play football, you don't ever want to be tight."

The losses of Campbell and Jefferson, in particular, are worrisome, as they were among the best players on the Cardinals a season ago. Even so, Arians isn't looking for the 2017 defense to simply match last year's production. He believes the unit can surpass it.

"I've felt great about this defense since the spring," Arians said. "The additions of Karlos and Antoine, and then the draft picks – we should be much, much better defensively."