After losing their offensive and defensive coordinators, the Vikings promoted one guy who recently came out of retirement, one who has spent not one of his 38 years in coaching as an NFL coordinator, and the head coach's son, who is 36 and has never before been a coordinator.

At first glance, you could be excused for thinking of these moves as a testament to NFL nepotism and cronyism sure to end in failure.

You should reconsider.

These moves are a testament to NFL nepotism and cronyism that have at least some chance of working.

The Vikings lost one coordinator to promotion and one via defection. Kevin Stefanski left to coach the Cleveland Browns. George Edwards, Mike Zimmer's longtime defensive coordinator, left because he wasn't given much responsibility or credit.

Zimmer replaced Stefanski with Gary Kubiak, and Edwards by promoting two current assistants — longtime defensive line coach Andre Patterson and linebackers coach Adam Zimmer, Mike's son.

Instead of conducting a national search, Zimmer walked down the hall and said, "What the heck?"

The last time Zimmer lost an offensive coordinator to a head coaching job, Pat Shurmur left for the Giants, and Zimmer got excited by the prospect of hiring a rising young assistant coach who had played a role in the Philadelphia Eagles' 38-7 victory over the Vikings in the NFC Championship Game.

Zimmer hired John DeFilippo, the Philadelphia Eagles quarterbacks coach. DeFilippo used the Vikings job to audition for a head coaching position, which meant trying to maximize the passing offense at the expense of the running game. Zimmer fired him before the end of his first season in Minnesota.

Zimmer installed Stefanski, then hired Kubiak as his assistant head coach and offensive adviser.

It could have been awkward. As far as any outsider could tell, it wasn't, which is a testament to the maturity of Stefanski and Kubiak.

Kubiak replacing Stefanski would not seem to be an upgrade, but under Zimmer it might be. Kubiak likely will be even more perfectly aligned with Zimmer's viewpoint. Kubiak won a Super Bowl as a head coach by relying on his defense, running game and nothing more than intelligent situational play by Peyton Manning.

Edwards was not viewed as an important player on the Vikings' staff. Patterson has long been the best of Zimmer's defensive assistants.

He will work alongside Adam Zimmer. He might be getting the job only because of his father, but as unfair as nepotism seems, sometimes it works. Kyle Shanahan probably got his first NFL coaching job because of his father, Mike. He also might be the best game-planner and play-caller in the league.

Coaching staff cohesiveness might be even more important than experience and ability to innovate. Zimmer has run off or lost a handful of offensive coordinators. It's hard to imagine Adam Zimmer, Patterson or Kubiak being anything other than helpful assistants for their head coach.

Here are the potential pitfalls of this staff structure:

• Installing Patterson and Adam Zimmer at the same position despite their dramatic difference in accomplishment and experience could turn out to be far more awkward than the Kubiak-Stefanski relationship. Patterson is a legendary defensive line coach trying out as an NFL coordinator while working with the coach's son. If the defense falters, who gets, and accepts, the blame?

• Zimmer is close with Patterson and, presumably, Adam Zimmer. With defensive backs coach Jerry Gray, another experienced veteran, leaving for Green Bay, who's going to provide constructive feedback to Zimmer? Will that fall completely to Patterson, and would he feel comfortable challenging his longtime friend and boss?

• With Zimmer and Kubiak the dominant coaches on the staff, is there a danger of the Vikings becoming too old-school? Are the Vikings' equipment managers ready to launder leather helmets?

This staff is set up to get along swimmingly, until the Vikings lose a few games.

Jim Souhan's podcast can be heard at TalkNorth.com. On Twitter: @SouhanStrib. • jsouhan@startribune.com