EAGAN, Minn. – There's been a lot of buzz about the Vikings new offense heading into 2019, but that doesn't mean the defensive side of the ball will be stagnant.

Minnesota is returning its defensive coaching staff and the majority of its defensive starters, but Vikings Head Coach Mike Zimmer is always looking for ways to improve and keep opposing offenses guessing.

"We're looking at a lot of different things," Zimmer told Twin Cities media members following Tuesday's voluntary Organized Team Activity practice. "I think that's part of what you do in the spring, is you look at things and you kind of, 'Hey, we could do this.' Or you look at the skill sets of different players. Most of our guys have been together for four or five years now, so I think part of that is keeping them engaged in everything we're doing."

Zimmer especially appreciates this time of year but joked that the rest of the coaching staff "doesn't particularly like it when I go away and start watching tape by myself" because it might mean an extra meeting or two.

"The other day I was coming back after Memorial Day, and I called a defensive meeting at 6:30 in the morning while I was on the plane because I didn't like how something was looking," Zimmer said. "But some of the things we're doing because I just feel like the way the offenses are moving now in this league and the things that they're trying to do, they're trying to scheme you, so I think part of that is that we always try to stay one step ahead of things. And now's the time to look at things and practice [them]. Whether it's a different technique, different personnel group, different alignments or different blitzes, pressures, things like that."

Zimmer explained that he studies other defenses and then evaluates how the Vikings can implement certain aspects on the practice field.

"You study a lot of other teams and see what they're doing and what looks good," Zimmer said. "And then you go back and correlate it to the types of plays that you've been getting all year long. We got a ton of a certain [type] of plays that people thought they could get on us, so maybe give them some different looks."

Here are four other topics Zimmer addressed during his podium session:

1. Danielle's development

Danielle Hunter impressed early on as a third-round draft pick in 2015, and he's continued to take major strides forward each season.

Still just 24 years old, Hunter's 40 career sacks are the most by anyone in his draft class.

Zimmer said that Hunter has always been someone who "never wants to make a mistake" but that his development has allowed him to play more freely and not worry as much about errors.

He offered the caveat that Hunter may still be "a little apprehensive" when asked to do something new, but he doesn't slow his game speed.

"In the past he would always, 'OK, I've got to make sure I do this,' and now if he makes a mistake, he's going to make it full-speed, correct it and move forward with it," Zimmer said. "You obviously see the athletic ability and the bend that he has, the long arms and the strength, and the way that he can slither through openings in the pass game – and in the run game."

2. Early impressions of Bradbury

Center Garrett Bradbury, whom the Vikings drafted 18th overall in April, has impressed so far during OTAs.

It's not always an easy transition from college to starting center in the NFL, but Zimmer said Bradbury has been doing "a nice job" with the jump.

"He's a very athletic guy that [can] really bend. He's got good power, he's very competitive," said Zimmer, who pointed out that Bradbury remained on the field to put in extra work. "He's done a good job. We're giving him a lot of different looks defensively, so I think that's good for him. There's times when we [confuse him a] little bit, but he's very, very bright and doing a good job."

3. Learning from 'Professor Dennison'

Media members are getting their first looks at Vikings offensive line coach/run game coordinator Rick Dennison in action.

The Vikings hired Dennison during the offseason, and he's been hard at work with Minnesota's offensive linemen. Asked how Dennison is doing with the group, Zimmer said, "He's a good teacher, number one."

"I think a lot of it will be with the schematic things, but as you get going in that and marrying the run game and the pass game … you can tell he's like a professor out there," Zimmer said of Dennison, who has a master's degree in engineering. "All the little intricacies of offensive line play, I think he's been outstanding."

4. Hercules impressing with help from Patterson

Zimmer has been impressed with Hercules Mata'afa, whom the Vikings have **moved from defensive end to 3-technique**.

Mata'afa signed with Minnesota as an undrafted free agent but suffered a torn ACL last spring prior to his rookie season. Now, he's working to make up for lost time and has caught the eye of coaches.

"He's just a worker. He's a guy that, he plays very low with his pads … his body lean is extremely low. He's got a great first step," Zimmer said. "You know, he's still got a ways to go, let's not put him in Canton yet. But he's doing a nice job for the things we ask him to do. He's got a great attitude."

Zimmer added that Mata'afa is benefitting under the tutelage of Vikings defensive line coach Andre Patterson.

"Andre's an unbelievable teacher. I was down here watching today and talking about those things, and I said to Linval [Joseph], 'Man, Andre's good, isn't he?' And he said, yeah, he wouldn't be where he was if it wasn't for [Patterson]. A lot of those guys feel that way. The more that [Mata'afa] can absorb the teaching that Andre's giving him, I think the better he'll be."