Cardinals running back Chris Johnson (right) talks to teammate Stepfan Taylor at Johnson's first practice Tuesday.

The message was clear to Chris Johnson from the first time he spoke to Bruce Arians on the phone. There would be opportunity in Arizona with the Cardinals, but that was it.

"We don't promise anything when we bring guys in," Arians said.

There were to be no guarantees of playing time, and little in guarantees, period, since less than half of Johnson's $870,000 is promised on his one-year deal. If the veteran running back doesn't work out, it would be easy for the Cards to release him at the end of the preseason.

Johnson insists he doesn't care. After signing a free agent contract last year with the New York Jets (with a $3 million signing bonus) and having that experience fizzle, after getting shot in a drive-by incident in March, after failing to make the playoffs in every year but his rookie season in Tennessee, the Cardinals still made the most sense as a destination.

"I don't say (I have) something to prove to somebody, I say something to prove to myself," Johnson said Tuesday, prior to his first practice with

the team. "With everything I went through, I'm just happy to be back playing football on Sundays."

He's not the runner who gained 2,006 yards in 2009 for the Titans, leading to his "CJ2K" nickname, although the only season he did not reach 1,000 yards rushing in a season was last year during a turbulent season with the Jets.

Johnson avoided getting much in depth about his time in New York, although he acknowledged he felt he had done enough to start there and wasn't sure why he did not. After averaging 4.3 yards a carry on limited work – 663 yards on 155 carries -- he also wasn't sure why so many believe he can't be productive.

"Losing a step, I don't see it," Johnson said. "I actually felt I was more explosive last year."

The Jets declined to pick up his option soon after Johnson took a bullet in his shoulder. Both men who were in the car with Johnson that night were also shot, one fatally. Johnson was on bedrest for six weeks, losing more than 20 pounds. When he first got back to working out, his arm was in a sling and was relegated to lower body work.

That rehab, done with trainer/FOX reporter Jay Glazer (who also worked with defensive end Calais Campbell this summer), was Johnson's refuge after getting shot.

"Of course, it changes how you look at life," Johnson said.

Arians said Johnson had been on the Cardinals' radar for a while, and not just because of the running back injuries that piled up early in camp – although it was tough not to notice that the lone running backs still hurt, David Johnson and Marion Grice, both returned to practice the day Johnson signed.

Arians said he had long admired Johnson's game, and that assistant head coach Tom Moore – who spent a season as a Tennessee Titans consultant – "loved the kid." Johnson is also durable, playing in 96 straight contests.

Asked about Johnson's physical, Arians was blunt. "There was nothing," he said. "Other than a bullet in his trap."

"A player will go through ups and downs in his career," said Cardinals coaching intern Rod Hood, who was a teammate of Johnson's in Tennessee. "I think this can rejuvenate him with B.A. and his schemes and how explosive (Johnson) is. I think it's a good fit for him."

Johnson loves the idea the Cardinals have so many offensive weapons, in particular a quarterback in Carson Palmer who is the best Johnson has played with in his career. He likes the idea that Arians enjoys throwing passes to the running backs, and he insisted he had no issues splitting time with current starter Andre Ellington.

Arians wouldn't rule out that Johnson could eventually start. His contract says that with 1,300 yards and a Pro Bowl appearance, Johnson could make up to $2 million. But it's more likely Johnson, assuming he makes the team, will be part of a rotation in the backfield.

Johnson understands those realities. He knew about them walking in the door, and it was not a deterrent.

"I just felt this was the right choice," Johnson said.