Cardinals linebacker Donald Butler takes part in the conditioning test on Thursday at University of Phoenix Stadium.

As coach Bruce Arians is fond of saying, it's a short elevator ride from the penthouse to the outhouse.

The Cardinals' latest addition knows the feeling.

Linebacker Donald Butler played so well early in his career that the Chargers signed him to a seven-year, $51.8 million contract extension in 2014. It devolved quickly, as Butler's numbers dropped precipitously the past two years and so did his playing time. The Chargers cut him in March, and it took until Wednesday for Butler to latch on with the Cardinals.

While Butler, 27, enters without any promises of even a roster spot, he plays a position that lacks depth, and joins a team that has made a habit out of turning late signees into productive pieces. Butler can look across the locker room at running back Chris Johnson for recent evidence of a reclamation project, and he would love to be next.

"Every season you want to come in and play well," Butler said. "Re-prove myself? I think there's some doubt out there, and I'm ready to prove the doubters wrong."

Butler and cornerback Mike Jenkins are General Manager Steve Keim's deep offseason veteran signings for 2016. Past hits include Johnson, tight end Jermaine Gresham, offensive tackle Eric Winston and linebacker John Abraham (not to mention last year's leading sack man, Dwight Freeney, five games into the season).

All of the pickups don't work, but the risk is low, and sometimes it turns out very well. Arians said the team is always scanning the available options.

"We've had success over the years adding guys that are now healthy to bolster the roster in case of injuries, and add competition," Arians said. "You can't have enough competition."

ARIANS NOT READY TO RETIRE

The Cardinals are on the short list of Super Bowl favorites heading into 2016. Arians is one of the NFL's older coaches, so he was asked if retirement would cross his mind if the team captures the championship.

"I'd never even thought about it, but I'd probably be more apt to try to get two," Arians said.

There are a few older stars on the roster creeping closer to retirement as well. Arians isn't sure how a Super Bowl would affect the decision-making process for players like quarterback Carson Palmer and wide receiver Larry Fitzgerald.

"I think that's up (to them) individually," Arians said. "From the way they've prepared and worked, I think it would be a time for a couple of them to maybe decide. I don't think that it would be hard to convince them to try to get two."

JOHN BROWN ADDED TO PUNT RETURN MIX

Star cornerback Patrick Peterson returned punts for much of last season, but the team didn't want him to take many risks after catching the ball, so his numbers weren't glamorous. There could be a change this year, as Arians said wide receiver John Brown will get a chance to return punts in training camp after excelling at the role in college.

Fellow speedy wideout J.J. Nelson had the job at times last year and will also likely be in the mix.

RUN TEST A BREEZE FOR CARDINALS

While Ravens wide receiver Mike Wallace made headlines by failing his conditioning test this week, the Cardinals had no such trouble, as the players breezed through their test on the first day back Thursday at University of Phoenix Stadium.

"It's nice not to have that one fat guy you've got to cheer for to see if he can make it," Arians said.

Arians said the players did a nice job preparing themselves physically for the season during their offseason break. The first training camp practice will be held on Friday at 2 p.m.

"We're ready to go," Arians said.