TEMPE, Ariz. — There’s no denying that Antoine Cason’s season has not exactly gone according to plan.

A mainstay in the San Diego Chargers’ secondary the first five seasons of his NFL career, the former University of Arizona star signed a one-year contract with the Arizona Cardinals, likely with the expectation of playing opposite Patrick Peterson as a starting cornerback.

Yet, when training camp was over, Cason found himself mostly playing special teams, occasionally contributing as a cornerback.

That’s all going to change over the team’s final three games, though, as the injury to safety Tyrann Mathieu means roles will change. Cason, in particular, is expected to see more time at cornerback.

“You just have to be ready to go, ready to play at all times,” he said. “And go out there and be confident.”

It would be understandable if Cason’s confidence was a bit shaken, especially given how he’s gone from someone who started all 16 games while recording 73 tackles and two interceptions last year to one who has just six tackles and one fumble recovery this season in a part-time role.

But Cason said none of that matters, especially right now as the Cardinals are fighting for a playoff spot.

“The situation is what it is,” he said. “We have a good chance to get to the playoffs so whatever my situation is, just trying to help the team get to the playoffs, get to our goal and play as hard as I can.”

Defensive coordinator Todd Bowles is comfortable with Cason’s expanded role, especially given the former first-round pick’s experience as a starter in the NFL. Cason has intercepted 12 passes in his career, and has never finished a season with fewer than two picks.

“When he went in last week he did a hell of a job in the slot and outside, so it’s just like going back to starting for him,” Bowles said. “He’s eager to play, he’s been making plays. It’s just a tough group to crack; he’ll get his chance this week.”

Cason is not the only one whose role will change some, as the coaches have said Javier Arenas and Jerraud Powers, among others, will see some different responsibilities with Mathieu out. Powers, who has been starting this season ahead of Cason, said he has little doubt the team will be able to manage without the star rookie because of the team’s depth.

“We’re pretty deep in the secondary, in my opinion,” he said. “A lot of guys that’s played a lot of football, and a lot of veteran guys, so I don’t expect there to be any type of drop-off because Tyrann’s out even though we’d love to have him on the field with us. But I think we’ll be fine.”

It’s been a theme all year, and it will hold true again. The “next man up” — whoever it is — is expected to play well when given the opportunity. And with the playoffs on the line, it’s imperative that all who play rise to the occasion.

“Just keep playing at all costs,” he said of the mindset going forward. “It’s been other guys that stepped up this year and played well. The secondary has been playing well all year. So just come in, play confident and continue to do what we’ve been doing all year.”

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