TEMPE, Ariz. – Three days before kickoff and the Arizona Cardinals remain, as does everyone else, in the dark as to whom they’ll face at quarterback in Indianapolis on Sunday.

This much is certain: It won’t be Andrew Luck. He remains out after offseason shoulder surgery. So, that leaves either backup Scott Tolzien or Jacoby Brissett.

For the Cardinals defense, it’s not an unfamiliar spot.

“I believe, the two times we played backup quarterbacks, we lost,” cornerback Patrick Peterson said, referring to a Week 1 loss last season against New England (Jimmy Garoppolo) and a Week 6 loss at Pittsburgh (Landry Jones) in 2015. “So, we understand the magnitude of this game facing a backup quarterback. We want to make sure that we’re going in there and preparing as if Andrew Luck is playing.”

Tolzien started the Colts opener, was intercepted twice — a pair of pick-sixes — and was sacked four times in a 46-9 loss at the Los Angeles Rams. Brissett played the fourth quarter and led the Colts to their one and only touchdown.

Just because Luck isn’t playing, the Cardinals don’t expect to see a brand new Colts offense.

“We don’t change our offense when Drew (Stanton) is playing,” head coach Bruce Arians said.

No, the Cardinals are preparing for the Colts, not the quarterback, according to defensive coordinator James Bettcher. Their concepts are the same, the formations, for the most part, he said, are the same.

Bettcher did admit, though, the Colts do some things a bit differently without Luck.

“They’re going to give you things where it’s Wildcat,” he said Thursday. “They’re going to motion the quarterback out of the backfield and snap the ball to one of the running backs in the backfield and you’re going to have to be prepared for that. They’re going to line the quarterback out of the formation and motion him back in … they’ve had a gadget or two out of it as well. You got to be prepared for those things.”

Tolzien is in his second season with the Colts, while Brissett just arrived prior to the start of the season in a trade with the Patriots. For that reason, Bettcher said, the Cardinals have watched some Patriots film to see what Brissett does well and what he may struggle with in terms of coverage.

Having quarterback Blaine Gabbert on the roster has also helped in the week’s preparation.

Gabbert runs the Cardinals’ scout team, so he can give the defense similar looks should Brissett play.

“He’s an athlete, so he can do a lot of things with some of these athletic quarterbacks and gives you a good picture,” Arians said of Gabbert. “Brissett’s not necessarily read-option, change of pace. He’s just a drop back passer who has good legs.”

The uncertainty this close to gameday does present its challenges.

“A little bit. I think they’re going to do pretty much what they do,” defensive tackle Corey Peters said. “Especially for a defensive lineman, we’re more focused on the run game and their protections … I’m not so sure that the quarterback really makes a difference for me.”

Dinner among friends

With left guard Mike Iupati missing a second straight day of practice Thursday, it appears the Cardinals may be without two of their starting offensive linemen. Left tackle D.J. Humphries isn’t playing after hurting his right knee at Detroit, while Iupati continues to be bothered by a triceps injury.

If Iupati can’t go, then seven-year veteran Alex Boone, whom the Cardinals just signed last week, will start.

“I like Boone,” offensive coordinator Harold Goodwin said. “The attitude he brings to the room has been great, it’s been awesome; and I feel comfortable with him.”

Boone has been a quick learner of the offense, according to Goodwin, because of 1) his experience and 2) a recent dinner with center A.Q. Shipley at Fleming’s Steakhouse.

“(Boone) paid for it,” Goodwin said.

That’s true, Boone confirmed.

“I’ve known ‘Q a long time. We came out (of college) together,” he said. “Just two guys having dinner, kind of talking about the offense.”

Most of Boone’s time in the NFL has seen him play left guard. So, in that regard, he’s very comfortable if called upon Sunday. Boone acknowledged he’s never been in this type of situation, where he’s playing only eight days after joining a new team.

“I don’t think I have a choice, do I?” he said. “I mean, in this league, does anybody really care if you’re not ready? So, I guess it’s better to be ready than not ready.”

John Wetzel, too, needs to be ready.

The backup left tackle struggled against the Lions after Humphries left the game in the first quarter. The hope is a full week of practice at left tackle — typically, Wetzel reps at multiple spots along the offensive line — will help avoid a repeat performance.

“It better help him a lot, alright? It better help him a lot because, obviously you guys saw what you saw, I saw what I saw and we were not pleased. And he knows and he’s not pleased,” Goodwin said. “At the end of the day, it doesn’t matter who’s out there, they got to hold up. When you’re playing that pivotal position of left tackle, that’s the money side of the protection, you got to hold up. He’s got to be a better job. He knows that.”

Robert Nkemdiche trending

Despite being limited for a second straight day in practice, defensive tackle Robert Nkemdiche (calf) is improving, according to Bettcher.

“It looks like he’s trending in a positive way,” Bettcher said.

Follow @CraigAZSports