TEMPE, Ariz. — There’s showing respect to your opponent, as is common across the NFL.

Then there’s how the Arizona Cardinals are feeling as they prepare to face Jimmy Garoppolo in his first NFL start on Sunday night — an abject fear of the unknown.

“The scary part is we really don’t have a lot on tape with Jimmy, as far as a real game plan, so we really don’t know what to expect,’’ three-time All-Pro cornerback Patrick Peterson said.

“He has the advantage there, because he can see all the film, everything that we do,’’ defensive end Calais Campbell said. “But we only get so much of him.’’

This is still Bill Belichick and the Patriots, after all. Even if Garoppolo didn’t have a lights-out preseason, and even though he won’t have Rob Gronkowski in the lineup, there’s still the thought in the back of the mind of every Cardinals player that maybe the Patriots were just holding back, and Garoppolo is going to come out shooting BBs.

“He showed flashes throughout all the preseason that he could possibly be really, really good,’’ inside linebacker Kevin Minter said. “It’s that wild card. It almost makes you, not necessarily nervous, but you don’t know what you’re going to get. So we just better knuckle up and be ready to play on Sunday. If not, we’re going to get embarrassed.’’

The Cardinals aren’t the only ones curious to see how Garoppolo does on Sunday, and throughout his four-game trial as Tom Brady’s fill-in. Garoppolo, the highest quarterback drafted by Belichick in his 17-year Patriots tenure (2014 second round), has thrown just 31 passes in two NFL seasons and has not played in any significant game situations.

It has presented an interesting challenge for Cardinals coach Bruce Arians and his defensive assistants, who somehow have to prepare for a quarterback who has produced little usable game tape, and figure out how different the Patriots offense will look with the switch from Brady to Garoppolo.

“As much of a disadvantage as it is for the Patriots not to have Tom Brady in there, there is a little disadvantage to Arizona as well, because they aren’t going to know exactly what to prepare for,’’ Hall of Fame coach Tony Dungy said.

Garoppolo had an uneven preseason, excelling against the Bears, struggling against the Panthers, and playing somewhere in between against the Saints. Overall he completed 36 of 54 passes (66.7 percent) for 406 yards, one touchdown, and no interceptions in three games, but Garoppolo certainly earned the Cardinals’ attention.

“He’s not a slouch, Garoppolo, by no means,’’ Minter said. “You hear people on Twitter trying to say we got this in the bag, but y’all mistaken. This kid is good.

“He’s been so accurate during the preseason. You remember when he came out [of college], there was a lot of hype on this kid. And there’s supposed to be, because the dude is that good.’’

So how do you prepare for the unknown? Arians said he and his coaches have been watching Patriots game film since May. And the Cardinals have to rely heavily on Garoppolo’s preseason game film, even if it doesn’t quite simulate the regular season.

Defensive coordinator James Bettcher said he and his staff created a highlight reel of every snap Garoppolo has ever taken, regular season and preseason, estimating it was about 256 total snaps. Included were the 12 snaps he played in garbage time against the Chiefs in 2014 — the only time he has thrown a regular-season touchdown pass — and the 35 snaps he played against the Bills in Week 17 that year.

Garoppolo played just 13 snaps all of last year, none of them useful to study. So the Cardinals have to rely on preseason film and hope it’s enough to get a read on him.

“It’s absolutely useful,’’ Bettcher said. “I think everybody has certain things they hold and don’t use and keep in their pocket, but I think from management of the game it’s very useful, how he reads keys, very useful.’’

Several Cardinals players and coaches gave a similar scouting report on Garoppolo last week, highlighting his quick release.

“Very athletic, very accurate,’’ Arians said. “Not a real powerful, deep throwing arm, but very accurate. Gets it out of his hand fast.’’

They also praised Garoppolo for his athleticism and ability to make plays with his feet. Arians compared Garoppolo to Tony Romo, another Eastern Illinois quarterback who makes plays outside of the pocket.

“Not to say Brady can’t scramble, but Garoppolo is quicker to run and you have to respect it,’’ Campbell said. “He can take it a lot more than 5 yards for a first down. He can take it 25 yards. You have to respect his athleticism.’’

But Tyrann Mathieu saw in the preseason what many Patriots fans saw in Garoppolo.

“We feel like he holds the ball a little bit too long,’’ said Mathieu, who will play on Sunday less than nine months after tearing his ACL.

And what will the Patriots offense look like with Garoppolo running the show instead of Brady?

“One thing I do know about the Patriots is they’ll try to expose certain weaknesses,’’ Chandler Jones said.

With Brady as conductor, the Patriots can spread a defense out with five receivers and pick apart the defense with short throws and runs after the catch. But with Garoppolo, Campbell is expecting power football — two- and three-tight-end sets, fullback James Develin paving the way as lead blocker, and a heavy dose of LeGarrette Blount as the Patriots try to put Garoppolo in manageable down-and-distance scenarios. Establishing the run will also help Garoppolo credibly sell his play-action fakes.

“You’ve got to assume they’re going to run the ball a lot, especially early in the game, allow him to get comfortable,’’ Campbell said. “You don’t want him coming out throwing the ball 40 times in the first game. If they do that, he must look really good in practice — which could happen, but I’m preparing for the run.’’

Peterson noted that the Patriots offense relies on “rhythm passing’’ and yards after the catch, and that the Cardinals’ defensive linemen might not have enough time to get to the quarterback. But Peterson is also expecting a run-heavy offense that relies on deception plays to give Garoppolo some time.

“Probably looking for boots, a lot more rollouts, things like that,’’ Peterson said. “Jimmy doesn’t have much on tape for us to look at but he’s very, very accurate. He moves very well with his legs, and defensive linemen just have to make sure they get their hands up.’’

Former Patriots executive Michael Lombardi, speaking Friday on WEEI, said he expects the Patriots to use a lot of no-huddle offense to keep the Cardinals defense on its toes and take advantage of personnel matchups.

And the Cardinals know that the Patriots will look for any way possible to move the football, conventional or not.

“We have to be alert for trick plays,’’ Peterson said. “Alert for the triple passes, alert for all the gimmicks, because at the end of the day, they’re going to have the mentality that they don’t have anything to lose.’’

The Cardinals seemed to spend considerable time last week devising ways to defend Gronkowski, and they are no doubt relieved that the tight end was left back in New England.

“There’s a bunch of other tight ends, but there’s only one Gronk,’’ Arians said. “He is a different animal when it comes to defending him.’’

“The guy’s more than a LeBron James at the tight end position,’’ Peterson said. “He’s the guy, whenever they’re in trouble, they want to get the ball to, especially in the red zone. We have to understand where he is and understand his positions, because where he is in certain formations, how he’s lined up is going to tell you what’s going to come. But as an athlete the guy is unreal. He’s done some things that receivers can’t even do. He’s going to end up shattering tight end records.’’

Now the onus falls on Julian Edelman to be the Patriots’ top play-maker, and Martellus Bennett, A.J. Derby, and Clay Harbor to try to replace Gronkowski’s production. Arians didn’t seem nearly as worried about Bennett last week.

“A really good blocking tight end, and a guy that’s caught the ball well at times,’’ Arians said of Bennett.

The Cardinals have been one of the NFL’s top blitzing teams for the last three years, and will probably attack Garoppolo from all different angles to try to fluster him and an offensive line that has several new pieces. The Cardinals are certainly looking forward to the challenge.

“Seems like he’s a pretty smart guy, he’s very mobile, and he’s going to make quick reads, get the ball out of his hands,’’ Campbell said. “You could tell he’s a good quarterback. There’s a reason he’s starting.’’

Ben Volin can be reached at ben.volin@globe.com. Follow him on Twitter @BenVolin