Whenever the Vikings are allowed to return to the huddle, a sturdy defense under coach Mike Zimmer will look to newcomers, many of them rookies, to help replace more than 4,500 snaps vacated by free agency.

Those Vikings rookies, from first-round cornerback Jeff Gladney to seventh-round defensive end Kenny Willekes, joined the team this past month in expanded classroom sessions, which ended this week. With tentative plans for a late July return for training camp, co-defensive coordinators Andre Patterson and Adam Zimmer know only actual practices will gauge the progress or the ground to be gained of a remade Vikings defense.

“I just want to get my hands on them,” Patterson said. “Be able to watch them execute the drills that I know are important for them to become great defensive linemen. Even though this has been great, and I know the guys mentally know what to do, now it’s about having the chance to get them to execute.”

Patterson and Zimmer were promoted to co-coordinators to replace George Edwards. They say the transition has been smooth. The coaches are separated by 24 years in age, but their relationship goes back nearly as long, to when Patterson, now 60, coached with Mike Zimmer in Dallas during the early 2000s.

“Both of us know Mike very well, and what he wants,” said Patterson, the former defensive line coach.

The co-coordinators have handled their own areas of expertise in meetings. Adam Zimmer, the former linebacker coach, added the young secondary to his duties. He worked this spring from the Zimmer Ridge Ranch in Kentucky alongside his father, who long had a focus on defensive backs. The Vikings used five draft picks on the secondary after five veterans left in free agency.

“Once in a while when we’re sitting on the back porch looking for deer, we get a football idea,” Adam Zimmer said. “He gets the notebook out and we say, ‘What about this?’ Or we get the whiteboard out. It’s been really good.”

An offseason program without practices forced coaches to get creative. Formats for meetings were tweaked weekly to keep players’ attention. Old training camp footage was dug up for teach tape. Rookie defensive linemen, in addition to veterans, had film clips presented by Patterson to illustrate strengths and weaknesses.

“I’m an old teacher. I started off as a teacher,” Patterson said. “We had to get into a teacher mode, not a coach mode. We’re going to be teachers and teach these guys what the scheme is all about, and I think that worked out very well for us.”

Offensive coordinator Gary Kubiak said he still scripted practices “like I was going on the field” to keep his mind sharp. With so many new faces, an additional focus for coaches is finding get-to-know-you time; 34 of 87 players on the offseason roster are in their first year in Minnesota.

“Probably the biggest challenge was having players get to know each other,” Kubiak said. “They know each other’s names, but they’ve never met. So we tried to have some interaction on the computer, talking about their lives, about their families, so that we can make up a little ground.”

With school out for summer, Vikings coaches are eager to put newcomers to the test.

“To see them actually go through what we’ve taught them over the last five or six weeks,” Adam Zimmer said. “See who can handle it; see who can’t. See who is going to rise to the top and who isn’t.”