Cardinals wide receiver Corey Willis returns a kickoff during Wednesday's practice.

Rookie kicker Matt McCrane has studied his fair share of kickoff strategy since joining the Cardinals as an undrafted free agent out of Kansas State in late April. It's now obsolete.

The NFL changed its kickoff rules on Tuesday to make the play safer, putting in place multiple restrictions for both sides. The kicking team has to spread out its cover men and have them all within a yard of the line of scrimmage, compared to the five-yard limit of the past.

The return team can't use a wedge to form a path for the return man and can't block in certain areas until the ball is touched or hits the ground. The Cardinals practiced using the new rules on Wednesday for the first time.

"Really, there's nothing to go off of," McCrane said. "I think it will be interesting to watch in the preseason, how teams work returns and how kickoff teams work coverages. That'll give us an idea of what we want to do, but it's a big change. I've never seen anything like it."

Coach Steve Wilks plans to talk with special teams coach Jeff Rodgers to figure out the best way to adjust. Wilks believes the new rules will allow teams to use smaller, faster players to cover kickoffs because there is no longer a wedge to break up, and thinks it could lead to more returns.

"What I'm seeing right now is like a glorified punt return," Wilks said.

The NFL also approved ejection standards for the use of helmet rule, in which players who lower their head to initiate contact can be penalized or kicked out. The rule could make it tougher on defenders, but the defensive-minded Wilks is on board with the change.

"We as a National Football League have to set the standard in how we teach (tackling), so it carries down all the way to the Pop Warner leagues," Wilks said. "I think it's going to be good. I think it's going to put a lot of onus back on the coaches to teach it the right way. ..It's about the safety and the integrity of the game that we're trying to clean up to protect these players."

NATIONAL ANTHEM POLICY CHANGED

The league also made a revision to its national anthem policy, requiring players and team personnel who are on the field to stand and show respect for the anthem. The policy states that personnel who choose not to stand for the anthem may stay in the locker room until it has been performed.

If team personnel are on the field and do not stand and show respect for the anthem, the club will be fined. The teams can then decide if a person's choice not to stand will merit punishment.

Players who kneeled last year were not punished because the act didn't break any rules, and safety Antoine Bethea doesn't think there should be any monetary ramifications for a similar gesture in 2018.

"I really do think fining players for expressing what they believe, I think that's kind of overboard," Bethea said.

Coach Steve Wilks plans to meet with team president Michael Bidwill and General Manager Steve Keim to further discuss the issue. Bethea believes there will be good communication.

"We sit down with Michael Bidwill all the time," Bethea said. "Michael Bidwill is really good with us, sitting down and listening to our concerns and things of that nature. He's been really good with us. I'm pretty sure we'll talk and we'll come to a happy medium like we always do."

Bidwill said last year's conversations with the players regarding the anthem were "invaluable." He addressed the policy change on Wednesday night from the Sanctuary Resort in Paradise Valley, where he was discussing Arizona's selection as the host for Super Bowl LVII. 

"We needed to do something," Bidwill said. "We wanted to respect all the parties around the issue, and we wanted our players to stand. The rule needed to be adjusted, which we did. So I think it's a good common-sense result which is a result of a lot of compromise and we are looking forward to moving forward."

HUMPHRIES, SEALS-JONES DON'T PRACTICE

Left tackle D.J. Humphries and tight end Ricky Seals-Jones didn't participate during Wednesday's practice but Wilks said neither suffered a setback. Humphries is making his way back from a season-ending knee injury last November.

"We always want to be smart with those kinds of guys, particularly D.J. coming off that knee," Wilks said. "It was just a day of rest for him."