Cardinals safety Tyrann Mathieu is playing a majority of the time in deep center field as he regains full health.

Tyrann Mathieu has made a life out of proving people wrong, and that's why this is so hard.

After a pair of Honey Badger-lite performances to open the season, there is a voice inside the Cardinals safety urging him to cut it loose. As the team prepares for Sunday's matchup against the Bills, Mathieu yearns to move back into his nickel back role – where he tracks wide receivers and blitzes unsuspecting quarterbacks from the slot.

"For me, it's all about competing," Mathieu said. "Coach tells you to run through a brick wall, you try to run through it, not knowing there are some consequences of running through a brick wall."

But for now, he continues to play the long game, acting as the last line of defense in deep center field, far from the bulk of the action. As much as he wants to mix it up, Mathieu is still just nine months removed from tearing his ACL, and knows the proper decision is to exercise caution rather than risk ineffectiveness or a setback.

"Even though I want to compete really bad … I just want to be mindful it's a long season," Mathieu said. "I'm sure my teammates would rather have me in December playing those types of positions rather than September."

Mathieu is the NFL's highest-paid safety because he can play a variety of positions extremely well. In order to move back into the slot, coach Bruce Arians needs to see the requisite speed and quickness from Mathieu, as well as a player who is banging down his door to return to that role.

"That hasn't happened," Arians said.

Despite the shackles, Mathieu was in a good mood on Wednesday, laughing with cornerback Tharold Simon as he walked into the Cardinals' locker room after practice. He continues to toe the line -- desperate to return to his impact form but smart enough to wait it out.

"Every day it seems to just eat at me, but I've got a lot of good guys around me who keep me encouraged, keep me in a positive spirit," Mathieu said. "I'm thankful for that."

BILLS HOPE PALMER HAS AN OFF DAY

Buffalo gave up 374 passing yards and a touchdown to Ryan Fitzpatrick in last week's 37-31 loss to the Jets.

Cardinals quarterback Carson Palmer is more talented, and will present another significant challenge for the Buffalo defense.

Palmer has thrown for 579 yards and five touchdowns with no interceptions this season after setting a career-high with a 104.6 passer rating in 2015.

"We're hoping for an off day," Bills coach Rex Ryan said in a conference call with Arizona media. "That's pretty much it. It's not a very comforting thought going into a game thinking that, 'Hey, this kid, we need him to have an off day,' but that's kind of where he is. He's such a talent."

RYAN REMEMBERS CARDINALS DAYS

Ryan served as an assistant coach for the Cardinals with his brother, Rob, under their late father, Buddy, in 1994 and 1995. The Cardinals only went 12-20 in those two seasons, but Rex said the experience was invaluable.

"I learned more football in those two years under my dad than all the years combined," Ryan said. "He was way ahead of his time that way, especially when it came to defense. … Even though the results weren't what we wanted it to be, it was clearly some of the best times I ever had."

MATHIS MISSES PRACTICE; VELDHEER LIMITED

Guard Evan Mathis (foot/toe) didn't practice Wednesday after leaving late in Sunday's win over the Buccaneers, while tackle Jared Veldheer (fibula) was limited. Defensive tackle Frostee Rucker (knee) and linebacker Kareem Martin (knee) also didn't practice.

Others limited were cornerback Justin Bethel (foot), wide receiver Larry Fitzgerald (knee), Mathieu (knee) and defensive tackle Robert Nkemdiche (ankle). Wide receiver J.J. Nelson (shoulder) was a full participant.

For the Bills, wide receiver Sammy Watkins (foot), tight end Charles Clay (knee) and tackle Cordy Glenn (ankle) did not practice. Safety Colt Anderson (foot), cornerback Ronald Darby (hamstring) and quarterback Cardale Jones (shoulder) were limited.