Corey Peters embraces getting older.

It's a little counterintuitive for a professional athlete, perhaps. But the Cardinals defensive tackle – now 31 and playing in his 10th season – had a very good season for a bad team in 2018, and his game continues to trend up as the years go by. That isn't an accident.

"When you're your (physical) best, you're 21 and 22 years old," Peters said. "You can run around all day but you don't know anything. You're just playing dumb, and you need to be quicker, honestly. As you get older and you lose a little bit physically, you make up for it with understanding angles and anticipating what's coming next."

Peters has been one of the most underrated free-agent signings the Cards have made over the last decade. He lost his first year he arrived, in 2015, because of an Achilles injury suffered in training camp. But he's been a rock in the middle of the defense and a captain in the locker room.

The first part of 2019 he's even been a pass rusher, notching a sack in Baltimore (with a noticeable dance he called the "Bernie") as well as his normal solid work as the first level of run defense. Pro Football Focus currently has Peters as the third-highest graded Cardinals defender after two games, behind safety Budda Baker and linebacker Terrell Suggs.

"He's a guy we count on doing things right in all aspects," defensive coordinator Vance Joseph said.

Peters was stung by the defense's inability to stop the run last season (metrics showed the team was much better at it when Peters was in the game), and the Cards have improved this season. But that was something that had to happen, Peters said.

"Every year, no matter who you are or what your situation is on the team, you have to improve," Peters said. "That's what we're looking for and that's what I'm steady striving for. I'm happy where I'm at, but I've still got a long way and a lot of stuff I can improve upon."

WITH CAM NEWTON OUT, KYLE ALLEN OFFICIALLY STARTS

The worst-kept secret of the week became official Friday when the Panthers listed starting quarterback Cam Newton (foot) as out for Sunday's game. Kyle Allen, who prepped at Scottsdale Desert Mountain High School and was a one-time college teammate of Cardinals Kyler Murray and Christian Kirk, will be Carolina's starting QB.

"We can't sleep on him," linebacker Chandler Jones said of Allen. "He's a good player. There's not a huge difference. This guy can run the ball and he can throw the ball. We have to prepare for him as well."

Allen spent a good chunk of his 2018 rookie year unemployed, but was signed by the Panthers late in the season and won his lone start, the 2018 season finale in New Orleans in which Allen completed 16-of-27 passes for 228 yards, two touchdowns and no interceptions.

"Either way they will be a formidable opponent," said coach Kliff Kingsbury, who didn't learn of the Panthers' official QB status until he walked off the practice field to the media podium. "The last time Kyle Allen stepped on the field they won and scored 30 points on the road. We understand we will have our hands full."

WITH JONES AILING, CORNERBACK COULD BE A CONCERN

Third cornerback Chris Jones, who had been added to the injury report as limited Thursday with a hamstring problem, was limited against Friday and is officially questionable for the game Sunday. The Cardinals are thin at the position if Jones cannot go – behind starters Tramaine Brock and Byron Murphy, they have only Kevin Peterson on the active roster.

Safety Budda Baker has played the slot before, and would be an option, although defensive coordinator Vance Joseph has made it clear multiple times he'd rather have Baker at free safety.

Offensive lineman Lamont Gaillard (knee) is the only player officially out for Sunday. Both defensive lineman Jonathan Bullard (hamstring) and linebacker Ezekiel Turner (hand/hamstring) are listed as questionable despite not practicing all week.

For the Panthers, safety Rashaan Gaulden (groin), tackle Brandon Greene (neck), linebacker Bruce Irvin (hamstring) and Newton didn't practice all week and won't play. Defensive end Kawaan Short (shoulder) also didn't practice all week but he is listed as questionable, as is tight end Greg Olsen (back).