Cardinals defensive tackle Frostee Rucker (92) talks with safety Tyrann Mathieu during a practice this week.

While in college at USC, Frostee Rucker majored in sociology.

"I'm a people person," the Cardinals' defensive tackle said. "I'm intrigued with how people think, how things are the way they are."

In a room with some inexperience and a void to fill after the departure of Pro Bowler Calais Campbell, it's easy to see the 33-year-old Rucker as the leader. The Cardinals, in fact, need that from him, and his understanding of people helps.

"When you talk about leadership, I call it being myself," Rucker said. "Sometimes you lead in different ways. My leadership is more they are comfortable around me and I play hard with them."

Rucker, though, has no desire to been seen only as mentor.

When he re-signed this offseason to a one-year contract, leadership was not part of the discussion with management. The Cardinals wanted a valuable contributor on the line, and Rucker was solid in 2015 on the field as a starter, totaling five sacks.

He wasn't the same player last year, battling a bad ankle and some knee issues all season. Frustrated and feeling like he let the team down, Rucker would rather talk about playing like he's capable this season than a role as a leader.

"I really, really want to dominate the playing field," Rucker said. "That's where my mindset is."

Sometimes, though, the role chooses you.

"He's always been the leader of that room," coach Bruce Arians said. "To have him in there, it's invaluable. You can't put a price tag on what he brings to the whole defense, not just the defensive line."

Rucker remains a starter as the Cardinals sort through a Campbell-less line. Tuesday, after a Monday practice in which Arians was not happy with the work on the offensive side of the ball, Rucker was supposed to have a veteran's rest day. Like wide receiver Larry Fitzgerald, who was in the same situation, Rucker dressed out and practiced instead.

"Frostee is just a laid-back guy who wants to have fun, but he's always preaching the importance of, when it's time to

work, it's time to work," defensive tackle Xavier Williams said. "He's on the field every day, year 12, on the practice field, banging it out. He may not be feeling it some days, but he understands we are looking to him, and if he is bitching and complaining it's probably going to trickle down."

The injuries made that more difficult last season. Fellow defensive lineman Corey Peters noted that Rucker struggled last season not only because of the injuries but also because the injuries limited Rucker – as an older player – to fully prepare for the season.

Arians sees the difference. Rucker is healthier than he has been in two years, the coach said. Rucker said he feels as a player he is peaking at the right time heading into the season.

He also wants to be a "dynamic teammate," however, which includes a big-picture view of the team.

"(Frostee) is not looking for accolades," Arians said. "He just wants to make sure we're doing it right. Tells me when he thinks we need something, which I respect. If he says we need to work harder or we need to work less, I'll listen."

That sounds like a player that knows people. And why Rucker smiles when he's asked if he plans to use his sociology background in the future.

"I'm using it every day," Rucker said.