EAGAN, Minn. — Vikings Head Coach Mike Zimmer on Friday emphasized his support for trying to keep Anthony Barr in a Vikings uniform for the long haul.

Barr was the first player drafted by the Vikings after Zimmer's hire in 2014. The two men have each had a role in Minnesota's worst-to-first transition on defense in a four-season span, but Barr is entering the final year of his rookie deal on an option that was exercised by the team.

"Anthony is my guy, number one," Zimmer said after Friday's walk-through session, which was moved inside Twin Cities Orthopedics Performance Center. "We are unequivocally not trying to trade Anthony. He's the first draft pick we ever had with me. He's helped this defense go from 32nd or 31st, or whatever it is, to being pretty good."

The Vikings won't be required to make any official statements on player injuries until the Wednesday before Minnesota's regular-season opener, but Zimmer said Friday that Barr had a "tweak" on Thursday, and "we kept him out of practice for a while."

Zimmer also elaborated on what he likes about Barr's game.

"Number one, he's smart as heck, so I can tell him to do all sorts of different things, make all kinds of different checks and adjustments," Zimmer said. "He's got great size, length and speed. He dictates the game in a lot of different ways that don't show up on the stat sheet, and to me, that's important, so we're trying to get him signed. Hopefully we can, but that's between upstairs and his people.

"We'd love to have him here," Zimmer continued. "Like I said, he's my guy, the first guy I drafted. I want him to get the best deal he can possibly get, but in a selfish way, I want him to be here soon."

Here are three other topics discussed by Zimmer:

1. Adjusting to new helmet rule

The NFL has implemented multiple rule changes for the 2018 season, and officials implemented them for the first time Thursday during the Hall of Fame Game between the Bears and Ravens.

One of the biggest changes is a rule that prevents players from lowering their helmet to initiate contact.

Zimmer said he took a look at calls that were made during the game. He is hoping that the preseason will enable coaches, players and officials to be on the same page.

"It's a concern because it looked like there was some, not sure of what is what," Zimmer said. "I did see a couple of plays that I thought were legit, and I saw a couple of plays that were questionable. It's going to be a work-in-progress all season, and they'll end up getting it right in the end."

An NFL officiating crew arrived at Verizon Vikings Training Camp on Thursday to meet with the team and explain the new rules. The crew, led by referee Pete Morelli, will be at camp through Saturday's scheduled night practice.

Zimmer said he communicated to the Vikings that it is important to not use the helmet as a weapon.

"The reason why they put that rule in, and I was talking to the team about it last night, was basically they don't want you to use the helmet as a weapon," Zimmer said. "They're trying to eliminate that from the game and make the players safer. I have no problem with that."

2. More difficult to be a DB

Additionally, the league announced it is making illegal contact (a defender interfering with a receiving target before the ball is thrown by the quarterback) a priority this season.

Zimmer said "obviously it's more difficult" to play defensive back now than when he entered the league as a defensive backs coach in 1994.

"The illegal contact, they're trying to clean up," Zimmer said. "I was on one of the committees where we sat and talked about illegal contact, pass interference, knocking a guy off a route, all of those different things. That rule has been in for a while. I think they're going to enforce it a little bit more and make it a little less ambiguous, I guess is the best way to say it, so that everybody kind of knows."

3. On the guards

With Nick Easton filling in at center while Pat Elflein recovers from offseason surgery and Mike Remmers missing Thursday's practice because of an injury suffered Wednesday, Tom Compton and Danny Isidora played with the first-team offense.

Asked how each has done, Zimmer said, "good."

"Compton, a lot of the stuff is new for him," Zimmer said. "He's working like crazy to catch on with everything we're doing and get more comfortable with the guys next to him. Danny has been playing a little bit of right and left. He's done a good job and needs to continue to progress."