EAGAN, Minn. -- Throughout the Minnesota Vikings' spring offseason program, Mike Priefer often woke up in the middle of the night, scrambling to jot down ideas that surfaced on his mind about new NFL rules designed to make the kickoff safer.
Thoughts of scheme and strategy creeping their way into his subconscious are common for Priefer, the former naval helicopter pilot whose strict attention to detail has Minnesota atop the NFL with the most special-teams touchdowns (14) since his arrival in 2011.
The questions he pondered spanned the spectrum: Will these safety measures lead to longer returns and fewer onside kicks? If you have a good return team, is your opponent more apt to try to kick touchbacks? If your kicker can put the ball high and short to the goal line with a 4.3-second hang time, how much easier is that to cover? If the returner you're facing is someone like Tyreek Hill, are you better served to try to kick it out of the end zone?
In March, NFL data showed that concussions were five times more likely to occur on kickoffs than on other plays in 2017. Two months later, Priefer was one of nine special-teams coaches to present a series of proposed changes to the rules on kickoffs and kickoff returns aimed at eliminating high-speed collisions.
As one of the league's longest-tenured and most well-respected special-teams coordinators, Priefer is on a mission to save all facets of special teams, starting with finding ways to preserve a part of the game the league has long tried to get rid of: kickoffs.
"How boring would it be to spot the ball on the 25?" Priefer told ESPN. "We had to find a way to keep this play alive and find ways to make it safer."
To the average fan, the new rules affecting kickoffs won't look that much different. To the 17-year NFL special-teams coach, the league will "absolutely" see injuries go down as one of the most dangerous plays in football becomes safer.
The NFL decided to fast-track these rules changes to put them in effect for the 2018 season, and that makes things tricky for all sides, from those teaching and executing plays to the referees tasked with enforcing the rules.
Preseason football has never been as important to special-teams coaches as it is now, with a chance to make adjustments to coverage and return schemes and see how kickoffs will be officiated. With something finally on tape after Minnesota's 42-28 victory Saturday in Denver, Priefer can begin to dissect where things went right, where they went wrong and learn just how different the kickoff will become with these new rules in effect.
Less than 24 hours after the Vikings kicked off their preseason opener, Priefer sits, clicker in hand, in Minnesota's special-teams meeting room, pouring through all 13 kickoffs exchanged between the two teams.
Two full weeks into training camp, Priefer wants to see where his players are with their understanding of the new rules and the areas he needs to focus on as the Vikings gear up to host Jacksonville this Saturday.
With so few examples of plays that reflect the new rules, Priefer and other special-teams coaches will spend the next three weeks carving out time to watch what others are doing so they can adapt concepts within their own schemes based on what's worked well for others.
For now, as he combs through the tape, Priefer explains how he's taught his players to adjust to the new rules and how it might affect the game going forward.
New rules for kickoff-coverage teams
The most obvious change is that the kickoff team no longer has a running start, meaning the unit cannot line up more than one yard from the line of scrimmage. On each kickoff that begins at the 35-yard line (where they typically do unless penalty yardage is assessed), Priefer looks for his players' feet to be on the 34-yard line and not an inch in front.
Until Kai Forbath boots the ball, all 10 players to his left and right (the new rule states five players need to be on either side of the ball, which limits schemes designed to get free runners in coverage down the field) need to have both feet planted on the ground as the kicker starts to approach. They don't have to be stiff statues, but each has to be cognizant to not have his helmet cross the restraining line.
"It's kind of a double-edged sword," Priefer said. "There's no room to get going. You have no momentum going forward, which is obviously very different for our guys."
If a helmet breaks the "pane of glass" officials deem the 35-yard line, a 5-yard penalty will be assessed for a player being offside. Late in the first quarter against the Broncos, Mack Brown was flagged for moving before the ball was kicked, which is much easier for officials to call now because everyone has to be stationary.
"I'm a hype guy, so I'm used to jumping up and down before the ball is kicked," Brown said. "Me standing still is kind of hard but you've got to stick to the rules for how they are."
The rules aren't second nature just yet for anyone, particularly rookies who were used to lining up at the 30-yard line in college. Priefer watched closely for this late in the game and found himself reminding fatigued players that they need to be on the 34-yard line and start behind the 35.
On a Denver kickoff later in the game, Priefer compliments the coverage team's ability to lean without going beyond the 35, a strategy used to making bursting off the line easier after the ball is kicked. He isn't shy about how nervous he is when teaching that tactic because of the miniscule margin for error.
To keep everyone accountable, Priefer has someone stand at the 34-yard line with a camera when his unit practices kickoffs. It's hard to argue with video evidence of a player being offside, and it's a helpful teaching tool to show players what they need to do differently when they line up.
Because players no longer have the 5-yard running start, Priefer has set aside ample time for the coverage team to get used to how the kicker will approach the ball from a much closer distance, just like an offensive line works to master a quarterback's cadence so the unit doesn't get slapped with a false start.
The emphasis now: Every player on either side, no matter whether they're in a sprinter's stance or standing straight up, needs to be looking inside for when the kicker connects with the ball.
One of the rules Priefer vouched for heavily at the player safety meeting in New York deals with the touchback. Three or four concussions occurred on touchbacks last year, according to Priefer, which the league was none too happy about. Now, when the ball lands in the end zone without anybody touching it, whether in the air or on a bounce, the referees blow the play dead.
Collisions often happened before on such kicks because players were colliding before the returner took a knee. With this rule in place, the play ends quickly.
The 'setup zone'
With the old rules, blockers on the receiving team were allowed to line up anywhere as long as they were behind their restraining line, which was 10 yards away from the kicking team.
Now, eight players on the return team are confined to a "setup zone," which starts 15 yards away from where the ball is being kicked. This makes blockers run down the field with the coverage team, eliminating high-speed collisions.
When the Vikings were set to receive a kick, Priefer lined up his personnel in a 5-3 formation (five players in front of three players) up front in the setup zone. He then positioned his two halfbacks (the labels he uses for players on the return team mirror positions on offense) deep and a returner in the end zone.
Unlike the players on the coverage team, those in the setup zone are allowed to move before the kick. Minnesota utilized its two players between the hashes to show motion in an attempt to keep Denver off balance. If they wanted to, all eight players in the setup zone could do the same.
"They could be the Rockettes in the middle of the field kicking their legs," Priefer joked.
The preseason is an important time for Priefer and other special-teams coaches to experiment with different formations in this area based on available personnel. He might choose to put a combination of eight defensive backs and linebackers in the setup zone based on whether he thinks his opponent is going to try a surprise onside kick. Priefer could choose to use a defensive end or tight end in these formations and move them far back within the zone so they can drop back more quickly and have more time to run to the player they're supposed to block.
Restrictions on blocking
The biggest change relating to safety has to do with blocking for the return team.
Wedge blocks began being phased out in 2009, when they involved three players. Now they're no longer part of the game.
The two deep blockers near the goal line are no longer able to team up with each other to create a wedge or join with any player in the setup zone to double-team a player on the coverage team. To keep track of the players who would be flagged for illegal blocks, in addition to giving the umpire the numbers of the players on his punt and field goal teams, Priefer is now responsible for letting the head referee know the numbers of the two blockers not in the setup zone.
"That's the exciting part. We don't totally know what it's going to look like. It's going to be different, and we get to be a part of creating that." Mike Priefer
As Priefer zooms through the film, he spots a near-penalty involving one of Denver's deep blockers. When Minnesota returned a kickoff with under six minutes to play in the fourth quarter, Priefer spotted a near-illegal double-team on Garret Dooley, when one of Denver's deep blockers got awfully close to joining up with a player from the setup zone.
"The official would not have been wrong to call it," he said. "I'm not going to get upset about this as a kickoff coach because [the deep blocker] bumped into him, but if he went down there and double-teamed if the ball went that way, it's a different story.
"It's going to be difficult [to officiate] for a while because I think they'll have to get used to the new rules."
Removing wedges and illegal double-teams are aimed at making the play safer, just as players cannot block within the setup zone until the ball hits the ground, if it's not caught first.
This is what will eliminate dangerous "attack" blocks that often result in cheap shots and blindside hits. Blockers on the return team now have to drop back farther to initiate a block, which the league believes will decrease major collisions.
Trying to get on the same page
At the start of training camp, the NFL republished its 2018 rulebook to clarify the interpretation of several kickoff rules. The changes weren't substantial; rather, they were aimed at making the rules more cut and dry for all sides to adhere to.
Priefer said the updates he got from the league during the summer dealt with three points of emphasis: The NFL wanted to make sure there was no lateral movement on the kickoff team, no wedges and that players on the return team didn't block until passing the restraining line.
"They just want to make sure we're all on the same page," he said.
It might take an entire season for everyone -- coaches, players, officials -- to get there, but the actions in place to make the game safer by not eliminating the kickoff, and instead remedying it, is something Priefer believes will benefit the game as a whole.
"That's the exciting part," he said. "We don't totally know what it's going to look like. It's going to be different, and we get to be a part of creating that."