GLENDALE, Ariz. -- There are things Tyrann Mathieu doesn't like to share publicly.

But the Arizona Cardinals safety opened up Wednesday, revealing one of the reasons why 2016 was so difficult for him.

"I didn't really like playing free safety," Mathieu said. "I didn't like being in the middle of the field. I feel like I came into camp and I'm really playing free safety like a free safety, so I'm getting better each and every day."

Coming off his second ACL injury in three years, suffered at the end of the 2015 season, Mathieu began the 2016 season as a free safety with limitations: He wasn't allowed to play in the box. That meant no blitzing, no man-to-man coverage, no playing the run. He was contained to playing center field.

Football got boring for him pretty quickly.

A season of playing center field didn't feel right to Tyrann Mathieu, who said, "I just like being in the mix of things." AP Photo/Matt York

"It's like everything is going on in front of you," Mathieu said. "I just like being in the mix of things. I had to challenge myself just to try to raise my game."

Mathieu spent this offseason putting in the time needed to prefect his craft as a free safety. He hadn't practiced at the position before last season. He hadn't worked at it.

He didn't take pride in it, he said.

Mathieu reported to training camp this year healthy and ready to play without restraints.

"I've challenged myself to really play the position and understand the position, and I feel like I'm getting better doing it," he said.

Mathieu feels like he's continuing to return to his old self, which means the Honey Badger of 2015, when he was in the conversation for defensive player of the year. Mathieu said he hasn't felt this good since then.

But he's not lamenting the time between then and now.

"It's life," he said. “I take the good; I take the bad. I don't outweigh them. I just try to balance it all. At the end of the day, it's life. I don't worry about it much."

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Mathieu's confidence is growing. His swagger is returning. Saturday’s preseason game will be another opportunity for him to get back into the groove. But Mathieu isn't sure how much preseason action he needs to get ready for the season.

"Anytime you get out there for eight or nine plays, it doesn't really do anything for you," Mathieu said. "I'm pretty sure we'll probably get the same number of reps this weekend, and hopefully when we go to Atlanta [on Aug. 26], we'll get a lot more."

Mathieu's plan at the start of camp was to take everything slow. It was going to be a long training camp. He knew he needed to pace himself, both on the field and off. There are outside expectations that Mathieu has tried to live up to, he said.

"I just try to quiet all that noise," he said.

But he also knows the way -- maybe the only way -- he can prove himself is by staying on the field. Then he can prove how good he can be this season.

"Well, we'll have to see," coach Bruce Arians said. "We'll have to see it in games. It's one thing in practice, it's another thing in games, the opportunities that he creates for himself.

"He should be back to the player he was."