Cardinals, Bruce Arians have deep thoughts

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Deep passing is in Bruce Arians’ DNA.

Consider 41 years ago, the Cardinals’ head coach was a quarterback at Virginia Tech who directed a run-heavy wishbone offense. Looking back, Arians acknowledges he much preferred heaves to handoffs.

“I always loved play-action and throwing it deep,” Arians said. “Those feelings have permeated throughout my entire career. Even if we have a short pass, there’s a deep-pass option. You just have to play smart and not scared.”

Yes, after failing miserably to defend the deep ball in last Sunday’s 43-18 loss at Pittsburgh, the 49ers will have plenty of chances to try, try again when they visit Arizona (2-0) on Sunday.

Last Sunday, Pittsburgh’s Ben Roethlisberger threw for 369 yards, had six completions of at least 28 yards and averaged 13.7 yards per attempt, the eighth-highest figure in the NFL since 2013.

Next is the Cardinals’ Carson Palmer, who ranks second in the NFL in touchdown passes of 70-plus yards (four) and ninth in yards per attempt (7.5) since he arrived in Arizona with Arians in 2013.

Cardinals quarterback Carson Palmer, a former Raider, ranks second in the NFL in touchdown passes of 70-plus yards (4) and ninth in yards per attempt (7.5) since he arrived in Arizona in 2013. Cardinals quarterback Carson Palmer, a former Raider, ranks second in the NFL in touchdown passes of 70-plus yards (4) and ninth in yards per attempt (7.5) since he arrived in Arizona in 2013. Photo: Jon Durr, Getty Images Photo: Jon Durr, Getty Images Image 1 of / 4 Caption Close Cardinals, Bruce Arians have deep thoughts 1 / 4 Back to Gallery

Niners safety Antoine Bethea knows what to expect. He played with the Colts when Arians was the Colts’ offensive coordinator and interim head coach in 2012. That season, Indy rookie quarterback Andrew Luck ranked fifth in the NFL in completions of 40-plus yards (11).

Bethea is ready for Arians, the 11th coach in NFL history to win two Coach of the Year awards, to go deep. At any time.

“That’s his style,” Bethea said. “He cares less about the down and distance. Third-and-2? He’ll take a shot. He’ll have some flea-flickers — that’s just the way he calls a game. So regardless of how our game would have been last week, we still would have been having to deal with deep balls and trick plays, or whatever.”

The 49ers will arrive Sunday after allowing their most points in a game since October 2009. The Cardinals, in contrast, scored their most points in a road game in 50 years in a 48-23 win at Chicago.

Arizona leads the NFL in points (79), hasn’t allowed a sack and has scored touchdowns on each of its seven red-zone possessions this season led by Palmer, who might be peaking just three months before his 36th birthday.

Palmer has thrown seven touchdown passes and one interception and has posted the NFL’s third-best passer rating (124.4). Dating to October 2013, Palmer, who missed 10 games last year with a torn ACL, has a 15-2 record, a 34-13 touchdown-to-interception ratio and a 99.0 passer rating.

Arians, the Steelers’ offensive coordinator from 2007 through ’11 when Roethlisberger was his quarterback, has been impressed.

“He’s probably playing at a level right now as good as anyone I’ve ever coached,” Arians said of Palmer.

What a difference two years make. In early 2013, Palmer was on his third team in four seasons and appeared to be a 33-year-old at the end of his career. He struggled to grasp Arians’ offense and threw 13 interceptions and eight touchdown passes as the Cardinals started 3-4.

On Wednesday, Arians said Palmer now has a “total grasp” of an attack that features wide receivers Larry Fitzgerald, John Brown and Michael Floyd.

“We’re in a totally different place than we’ve ever been in this offense,” Palmer said. “Just everybody, across the board, from the backup tight ends, to the starting receivers, to the running backs.”

The same can’t be said for the 49ers’ defense, which didn’t register a sack or hit on Roethlisberger on Sunday while allowing 252 yards passing in the first 27 minutes. Arians and Palmer, predictably, dismissed any suggestion the 49ers might be vulnerable, carrying on the NFL tradition of not providing pregame bulletin-board material.

“I don’t see any weaknesses anywhere,” Arians said.

Offered Palmer: “Everyone has a game like that where you just are off a little bit.”

Not surprisingly, the 49ers are also taking an optimistic view.

“From them watching the film, they’re going to think they can throw the ball up on us,” Bethea said. “A plus for us is that’s more opportunities for us to go out and make plays.”

Eric Branch is a San Francisco Chronicle staff writer. E-mail: ebranch@sfchronicle.com Twitter: @Eric_Branch