Running back Chris Johnson (23) will get the start Sunday with Andre Ellington (38) sidelined because of a knee injury.

Bruce Arians likes the idea of having rookie running back David Johnson in his role, which means veteran Chris Johnson not only will start in Chicago Sunday, he should get the majority of the carries.

In fact, with Andre Ellington officially out against the Bears because of a knee injury, Arians acknowledged he would have likely given Kerwynn Williams – currently on the practice squad – the start and not David Johnson if the Cardinals had not signed Chris Johnson.

"If we didn't have Chris we'd probably turn to Kerwynn because he's done it before," Arians said, "and keep David in his role. (David Johnson's) role has expanded (this week) and it should expand every week now."

Against the Saints Chris Johnson had 37 yards on 10 carries, almost all of them coming after Ellington went down. David Johnson did not have a rushing attempt, although he was targeted twice in the passing game and scored the game-clinching touchdown on a 55-yard catch-and-run.

"Those guys are going to get it done," Ellington said. "No doubt in my mind."

Last season Johnson, playing with the Jets, had just six games in which he had more than 10 carries in a game. Of those games, he cracked 100 yards once (on 17 carries, in a 16-13 loss to Miami) and totaled 377 yards on 82 carries (an average of 4.6 yards a try.)

Ellington said he wasn't sure how long he will be out. He said it could be two-to-three weeks, although he's satisfied with looking at it "day-to-day" right now. He did not practice all week, but Arians said that was in part because the Cards practiced on the turf inside their practice bubble all week.

Guard Mike Iupati (knee) was limited again Friday, but he will not make the trip either.

Safeties Deone Bucannon (groin) and Tony Jefferson (hamstring) also were limited and Arians called both game-day decisions.

BEARS HURTING THEMSELVES

The Bears also had some in-week injuries crop up to leave some key players in doubt for Sunday's game. Top wide receiver Alshon Jeffery (hamstring, calf) and pass rusher Pernell McPhee (wrist) each had to sit out Friday's practice and are questionable for Sunday's game.

Defensive end Ego Ferguson (knee) is also listed as questionable. Linebacker Jonathan Bostic (ankle) and cornerback Tracy Porter (hamstring) are listed as out.

BUTLER SETTLES IN WITH HIS PUNTS

Punter Drew Butler was wearing a Cardinals hat in the locker room, an old-school version of team gear circa 1997– he found it in the garage of his father, Kevin, who kicked for the Cardinals from 1996-97. And Kevin Butler will be at the Cardinals-Bears

game Sunday as part of an alumni event for the Bears, for whom Kevin kicked for the majority of his career.

Drew Butler is happy to be part of the trip. It wasn't a lock, battling Dave Zastudil in training camp. Then Butler got off to a rough start against the Saints with a 30-yard punt on his first 2015 attempt. After that, though Butler did well. He hit a 47-yard punt with major hangtime and dropped two inside the 20 – including his final kick that was downed at the New Orleans 3-yard line.

"(Bad punts) are bound to come up every now and then," Butler said. "You have to trust in your ability. I had a great training camp, felt really good through preseason. I knew exactly what I did (wrong) and went out and corrected it, and felt like, as a punt unit, we did really well.

"If I had done something different on the first punt we'd be sitting in a better positon (statistically) but limited return yards, lot of fair catches, punts inside the 20, helping the team win the game is really the only focus."

PALMER ON THE MOVE MAY BE INEVITABLE

Quarterback Carson Palmer gave everyone a pause with how much he scrambled Sunday against the Saints, in particular his 12-yard scramble at the end of the first half in which he came up limping. Turned out, Palmer's knee brace got caught in the turf on the slide and dug up a chunk, and his limp was about readjusting his brace.

Arians said Palmer's runs probably cannot be avoided.

"You've got to play the position," Arians said. "The one before the half I would've liked to see him throw the ball and kill the clock, but the others were outstanding getting out of the pocket. He extended the play for the touchdown on the first drive and didn't put himself in harm's way, other than that one terrible slide."