NFL training camps didn't have terms like "acclimatization period," "gradual ramp-up period" or "contact integration period" back in 1994 when Mike Zimmer left Washington State to coach nickel backs for Barry Switzer's Dallas Cowboys.

Those are new-school guidelines that were agreed to by the NFL and its players association heading into a 2020 season that's trying to bob and weave its way through a worldwide pandemic.

But there will come a day — Monday, to be exact — when old-school Zim will be allowed to put aside social distancing, turn back the clock and order his millennials to practice like it's the 20th century.

"Number 1," he said, "we're going to have live contact."

On Wednesday, teams shifted from the "acclimatization period" (a fancy word for conditioning with strength coaches) to the "gradual ramp-up period" (fancy words for football drills led by football coaches).

After two days of individual on-field training, non-padded practices with helmets and shells will be held Friday and Sunday with an off day in between. And then the "contact integration period" begins.

A maximum of 14 padded practices can be held through Sept. 6 with specific off days mandated by the new collective bargaining agreement. Practice periods start at 90 minutes and can increase by 15 minutes daily up to 120 minutes. Practice times can't be increased after days off.

"Without preseason games, we're going to have to set up [live] situations throughout practice," Zimmer said. "We're going to have to evaluate guys with some of our younger guys against our better guys and try to evaluate those players in those situations. So the evaluation part will probably be the biggest thing for a lot of these young guys."

Relax, new-schoolers.

Kirk Cousins will still wear his red jersey. Even in the league's Neanderthal Era, QBs were off-limits in practice.

And don't worry about wear and tear on Dalvin Cook's wheels. He'll still be protected like a vintage Ferrari as some of the other fellas smash into one another like station wagons in a demolition derby.

The action on the line of scrimmage will be especially intense, even for the starters. But that's par for the course.

If there is actual live tackling, you can bet it won't involve Harrison Smith clobbering Adam Thielen over the middle. More like Brian Cole II blasting into Dan Chisena as Harrison and Adam head toward the cold tub.

Accurately judging this deep rookie class won't be easy. But coaches are hopeful, hearkening back to their college football coaching days when starting lineups and game plans were hatched in three or four weeks before the season opener.

One rookie to watch in all of this is second-round draft pick Ezra Cleveland. The left tackle of the future doesn't have time to beat out incumbent Riley Reiff, but he will have a chance to win the open competition at right guard, a position he's never played.

Offensive coordinator Gary Kubiak was asked if the Vikings can accurately judge Cleveland's ability to play right guard without preseason games.

"Yeah, I think we can," he said. "Zim and I have talked through that. How do we go about getting those answers as quick as we can?

"Though we don't have preseason games, I think any coach would tell you that the practices are going to ramp up. And the fact you're not stopping to play a game every week, you're probably going to be able to have some more intense practice time. So I think you got to take advantage of that, do everything you can to create game situations and try to get some early answers."