GLENDALE, Ariz. — It wasn’t good that the Arizona Cardinals allowed the Los Angeles Chargers to average 6.4 yards per rush in the preseason opener.

It wasn’t great that the Chargers’ trio of backup quarterbacks accounted for 89 of those yards.

The game did, however, bring up a point about the value of preseason games as the Cardinals defense readies to face more traditional offenses compared to what it faces every day in practice.

“It was our first real time out there facing — I won’t call it an NFL offense, but a more traditional offense versus four-wide all the time, spread all the time,” cornerback Patrick Peterson said. “We had to get our eyes right … guys were moving a lot, gaps were moving a lot. Now we have something to teach off of.

“That was a PhD running game we had to face. We never really saw any slashes, no pulls (in training camp) because we’re practicing against our offense. It was a different look for us, but I think now that we understand our gaps … we’ll be more sound.”

Arizona head coach Kliff Kingsbury said there’s no reason to panic, and the slog of the preseason that has three more games left is proof that there’s plenty of time to shore up run fits and principles in defensive coordinator Vance Joseph’s 3-4 scheme.

The Cardinals face another NFL traditionalist in Jon Gruden’s Oakland Raiders this week. While helmet-seeking receiver Antonio Brown isn’t on the menu for Oakland, the Cardinals will be facing Gruden’s mix of 1990s and 2000s offensive philosophies of dual-tight end sets, downhill running and the like. Oakland had two running backs on the field 20% of the time last year and also relatively frequently used 2-2 personnel, with two backs and two tight ends.

But Gruden, who proved last year in Oakland that he evolved while working as an ESPN analyst, will also spread things out and use pre-snap motions that can challenge the Cardinals.

Still, practice is where Arizona’s new coaching staff will be earning its money.

As the regular season nears, Joseph and his assistants will be challenged with providing enough teaching moments to prepare the Cardinals without a whole lot of live reps.

“This league is a lot of walk-through based,” linebacker Jordan Hicks said. “You got to walk through, you got to be able to learn and focus when you walk-through. When we’re scouting and we’re game-planning for a team, we’re going to have those looks. That’s what’s unique.

“I know people lose sight about (it) in the preseason — we’re getting run on. But we’re not game-planning these guys. Really, we’re not worried about the other teams. We’re worried about ourselves.”

The Cardinals believe that seeing rookie quarterback Kyler Murray and frequent 10-personnel sets in practice will help them improve. But along with doubts about Kingsbury’s offense, how facing that offense every day affects the defense won’t be known until Arizona faces the Detroit Lions in September.

“I think no matter what we go against it’s going to make us better,” defensive tackle Corey Peters said. “We just have to make sure that although we’re going against this offense in practice, we also get some looks against some more pro-style offenses and some of the things we’ll probably see more week in, week out in the league.”

Follow @kzimmermanaz