Invariably, when a new defensive coordinator is hired, he vows to be more aggressive than his predecessor. Sometimes that promise is validated. Oftentimes it’s just rhetoric.

There’s nothing ambiguous about new Arizona defensive coordinator Don Brown’s message or approach. They don’t call him “Dr. Blitz” because he regularly drops eight defenders into coverage. Brown’s philosophy is simple and direct.

“We’re going to solve our problems with aggression on the field,” he said.

Brown estimated that his defenses have brought pressure — more than four rushers — around 60% of the time over the course of his coaching career. That has led to consistently high overall defensive rankings and sack rates — foreign concepts at Arizona in recent seasons.

Brown even has proved he can engineer quick turnarounds. That leads to the latest in our series of questions about the Wildcats heading into spring practice, which begins Tuesday:

How quickly can Don Brown create a legitimate pass rush at Arizona?

Everything in Brown’s record suggest it’ll happen sooner than later.

Starting with the 2011 season, Brown’s defenses at Connecticut, Boston College and Michigan produced at least 2.54 sacks per game for nine consecutive seasons. They ranked inside the top 35 nationally in that category each year.

Over that same span — 2011-19 — Arizona reached 2.54 sacks per game only once. The Wildcats averaged 2.71 sacks in 2014, when Scooby Wright alone had 14.

After a promising spike in 2017 — 2.38 — the UA pass rush has produced diminishing returns: 1.92, 1.42 and 0.40 over the past three seasons. The Wildcats had all of two sacks in their five games last year.

Brown and the defensive staff, under Jedd Fisch’s direction, have added talent to the defensive front. The newcomers include veteran linebackers Treshaun Hayward and Jerry Roberts, from Western Michigan and Bowling Green, respectively, and long-levered defensive end Jason Harris from Colorado.

Still, Brown has his work cut out, especially in Year 1.

“I’m hopeful that he can bring it right away,” Fisch said. “I am 100% confident in Don and the defense. He’s shown that he’s been able to build things over a few years’ time.

“I think it will come. I think we’ll be an aggressive defense right away. I think we will play extremely hard right away.

“As I said the other day, how do I envision success? I envision us being the hardest team everyone plays on the schedule, the toughest team everyone plays, the most challenging team. That comes from playing great defense and having an attitude, which I think Coach will probably bring right away.”

That attitude has been evident in Brown’s handful of interactions with the Tucson media. While discussing the foundation of his defense — everyone running to the ball on every play — Brown had to pause to calm himself down.

Regardless of whether Arizona has the personnel — pass rushers and cover men — to successfully run his system in 2020, Brown isn’t going to change his ways. He’ll undoubtedly tweak the scheme once he gets a handle on the Wildcats’ personnel; he has referred to it as “multiple” on multiple occasions. But the goal will remain the same: to play on the other side of the line of scrimmage and make opposing quarterbacks uncomfortable.

“Coach Fisch and I share a similar philosophy on how the game should be played,” Brown said. “That’s why I’m here. He believes in … being aggressive and playing through your defense.

“In different stops I’ve made over my career, the important thing is to stay true to yourself and stay true to your beliefs about this game. And that’s what I’m going to do.”

Brown’s approach has worked at every stop. Assuming Arizona’s isn’t unfixable, it’ll work here, too. It’s more a matter of when than if.

The when is just difficult to pinpoint.