Mike Zimmer knows the Vikings had one of the NFL's most unproductive offenses in each of his first three seasons in Minnesota. And he knows they need to fix their offensive line for that to change in 2017. But…

"Obviously, we're going to look very hard at the offensive line there. We'll look in free agency and all these places to fill holes," Zimmer said yesterday here at the NFL scouting combine in Indianapolis. "But I just want to be extremely careful that we don't rob Peter to pay Paul."

In this case, Peter would be a Vikings defense that has been the strength of this team since Zimmer arrived in 2014 and was one of the NFL's best the first half of 2016 before running out of steam down the stretch. As long as Zimmer is here, that will be the foundation of the Vikings.

"We don't ever want to slight that side of the ball," he said. "We want to make sure that continues to be a strength for us and add to the other side. So when we get down to it, we're going to try to figure out the best player we can pick wherever it is. It might be another corner or something like that."

The team's two most pressing needs are on the offensive side. They need to bring in a few capable bodies on the offensive line and running back will be a priority with Adrian Peterson hitting free agency.

But they do have needs on defense — lesser needs, but needs nonetheless.

They must add cornerback depth if they lose Captain Munnerlyn and/or Terence Newman. Munnerlyn should have strong suitors in free agency, pushing him out of their price range. Newman, who according to Zimmer wants to keep playing in 2017, seems more likely to re-sign.

Zimmer said he would be comfortable with Edmond Robinson and Emmanuel Lamur competing to replace Chad Greenway at the weak-side linebacker spot in the base defense, assuming Greenway still plans to retire. But they might still want to add another linebacker to the mix.

They need a disruptive defensive tackle because they can't count on Sharrif Floyd, who should be back in 2017, to actually stay healthy.

And with Brian Robison nearing the end of the road, Zimmer might want to nab another project at defensive end to develop into a future starter like he has done with Danielle Hunter the past two years.

Make no mistake, the Vikings are expected to use most of their resources on offense this offseason after using six of their nine draft picks in the first three rounds of the last three drafts on defense. But don't be surprised if at least one of their early draft picks is used on a defender.

Also on the Peter and Paul front, Zimmer is trying to find the right balance this offseason when it comes to becoming more hands-on with the design of the offense. He does not want to ignore his baby, Peter, the defense. But he feels he can help the offense improve this season.

"I've gone through every offensive game twice that we played last year myself," Zimmer told us local guys yesterday. "In the mornings, I would sit in with the offense. We'd go through cut-ups, playbook installation, those things. And then in the afternoon I do it with the defense.

"Basically, what I'm trying to do is get a better overall feeling of how we do things offensively, but also try to give them an opinion of the way defenses look at certain things and things like that. I'm just trying to be an extra resource in the room of a guy that kind of knows defenses."