Mike Priefer, special teams coordinator for the Vikings, just got a busier offseason. In addition to the new national anthem policy, the NFL also adopted rule changes that will tweak the way teams deploy kickoffs and kickoff returns.

In Minnesota, the frequency of kickoff returns is in steady decline. Within the past decade the NFL has adopted a handful of rule changes to alter one of the game's most dangerous plays. The Vikings have fielded fewer kickoff returns every season since 2013, when Cordarrelle Patterson took the bulk of 66 returns.

Last season, the Vikings attempted just 25 returns.

Still, the NFL competition committee is keeping the play while continuing to enact safety-driven rule changes for 2018.

Every team will need to adjust. One of the Vikings' 2017 kickoff returns, in the Dec. 10 loss at Carolina, had a handful of setups and actions by the Panthers and Vikings that will now be considered illegal by officials.

First, defensive linemen Shamar Stephen and Stephen Weatherly (starting at their own 20-yard line) drop back to form a two-man wedge (the three-man wedge was done away in 2009). That will now be outlawed altogether.

-A wedge, defined by the NFL as aligning shoulder-to-shoulder within two yards and moving forward together to block, is now illegal in all capacities. Only players who line up within 25 yards of the kickoff can block a single opponent together.

Second, the Vikings only have six players lined up near the kickoff. They've previously kept at least four players farther back (along with the primary returner) to help form double-team blocks behind the front line.

-The receiving team must now have eight of its 11 players within 25 yards of the kickoff point.

Third, the Panthers' kickoff team gets a running start by lining up five yards back.

-Players on the kicking team now must line up within one yard of the kickoff, all but eliminating the running start. The Vikings had also taken full advantage of the running start on kickoff coverage prior to this upcoming season.

The batch of rule changes doesn't figure to affect the number of returns, as others have while enticing touchbacks and moving up the kickoff line. Can the play become more explosive again? Perhaps eliminating the kickoff team's running start can help open space for returners. The NFL still saw seven kickoffs returned for touchdowns in 2017.

"I personally think it's going to make it a more exciting play," Vikings general manager Rick Spielman said on KFAN this week. "They don't get the run-up. Then you have to have eight guys in that 15-yard zone, which is going to make it more like a punt. I think it's going to actually create more kickoff opportunities."

Here are other tweaks to the play:

-There is no more blocking allowed within 15 yards of the kick. Teams, like the Chicago Bears in the season finale at U.S. Bank Stadium, have previously sent one or more return members on 'kamikaze' blocks. Return members can no longer run straight at the kickoff team after the kick.

-If the ball hits the ground in the end zone, it's immediately ruled a touchback. Previously, a player had to recover the ball and either return it or take a knee.

Here's the complete rule proposal that was approved.