Vikings defensive coordinator Brian Flores says he doesn't want to overload young players as he leads the unit's overhaul, one that promises to bring an array of formations within a thick playbook.

But there's no confusing how Flores wants Vikings defenders to play.

Since being introduced in February, Flores has consistently preached an aggressive approach to describe the direction he is moving last year's 31st-ranked defense.

Running back Alexander Mattison chose a different word after two organized team activity sessions in Eagan this past week.

"It's intense," he said. "Mentally from the backfield looking at that defensive front, those [line]backers and how they're moving around. The way they're lining up out of the gate is very intense. … I mean, I love to see it. For other teams, it's going to be a problem."

Flores and defensive coaches are currently laying the groundwork for reprogramming a Vikings defense often criticized last year for being too passive under former coordinator Ed Donatell.

Changes range from small details — how players take their first steps and where they place their hands and eyes after the snap — to major schematics and an overall attitude adjustment.

"[We] are installing an aggressive style," Flores said. "Building an identity is a big part of playing defense in this league. It's early, but that's a part of it, too. … That happens over time. Every time you step on the practice field, what is our identity? What are people going to say about us? Not that we're worried about that, but what do we want it to look like?"

"They understand my nature of wanting to be aggressive, but not reckless," he added.

Defensive changes were apparent during the first OTA session open to reporters Tuesday. Gone were last year's off coverages and indiscernible movement. During practice, linebackers and defensive backs roamed to different spots depending on the play call. Personnel groupings included three-corner and three-safety sets. Receiver K.J. Osborn called the coverages "exotic."

No live contact or shoulder pads are allowed in these first 11-on-11 practices, which limit evaluations for coaches. But Flores said they can see how quickly a young roster translates weeks of classroom and technique work into full-team sessions.

And there has been much to learn, said second-year cornerback Akayleb Evans.

"You never know where you might end up on the field," he said. "You might have to understand corner and safety and the nickel spot — just be versatile. And I like that, because it expands you as a football player, and I feel that's how you make money in this league. So I'm all for it."

As Dolphins head coach from 2019 to '21, Flores established a blitz-heavy identity with groupings of five and six defensive backs on the field at once. Evans is one of many young Vikings defensive backs vying for playing time this summer, including safety Lewis Cine and cornerbacks Andrew Booth Jr. and Mekhi Blackmon.

While young players are being taught multiple spots, Vikings coaches internally discuss how to structure reps to build confidence, according to Flores.

"Let's learn this one thing," Flores said. "Let's get good at this, let's get comfortable. Let's get confident in this one spot. … You can cloud their minds pretty quickly."

Growth can also happen quickly as Flores learns more about a Vikings depth chart in which nearly half of defenders — 21 of 45 — are first- or second-year players.

"[Rookies] don't know what 494 is, or 35W," Flores said. "They're trying to get acclimated and figure things out. There's a lot of development there and they can develop quickly because they don't know as much. .. [We're] finding out the things they do well, what buttons to push, what buttons not to push."

The defensive changes could skew the outlook of the Vikings offense, which ranked seventh in yardage and eighth in points during coach Kevin O'Connell's first year calling plays.

"We weren't seeing those [diverse looks] last year," left tackle Christian Darrisaw said of practices, "and we'd kind of get into games and teams would run a certain defense and we were negatively affected."