The NFL and the NCAA have made a lot of rule changes over the past few years in an effort to increase player safety.

Two-a-day practices are a thing of the past as of last year.

Tackling all the way to the ground is not something many programs practice on a regular basis.

So it shouldn’t be surprising when you show up to OU’s practices only to see most players wearing what looks like the equivalent of bubble wrap around their heads.

The Sooners are wearing football caps as an outer shell to their helmets that absorb contact made by the company Guardian.

For some players, the caps are mandatory.

“We have put them on all of the front seven defensively, mandatory, we've put them on everybody on offense but our quarterbacks, receivers and of course if guys have wanted it outside of that, we've let them do it,” explained Lincoln Riley.

Guardian claims their caps reduce impact up to 33%.

“There's not as much pop,” explained one of OU’s middle linebackers, Caleb Kelly. “So I guess there's not that much jarring going on.”

Guardian also claims the caps “pad blows to the knees, hands, abdomen, etc. during Inside Run and position drills”

The Sooners didn’t start out using the Guardian caps to limit potential concussions.

“We've had these helmet pads for a little while,” said Riley. “We've traditionally used them for breaking in game helmets, like give you an example, a week where we're gonna use the alternate helmets, we'll practice in them that week just to not scuff them up. That's how they've been used.”

But Scott Anderson, OU’s Head Athletic Trainer, and Brock Schnebel, OU’s Team Physician, have been at the forefront of concussion research over the last decade.

“Darn near every kind of research we look at has their names cited at the bottom,” Riley said of the men who decided the Guardian caps could become something that could be more preventative for the Sooners’ players.

“Through some research that Scott and them we're made available, we thought there was gonna be some advantages to wearing those, potentially reduce some of the collisions.”

So now the Sooners aren’t just keeping their helmets clear, they’re keeping their heads clearer.

“They said you're wearing this and if you take it off you're getting out,” said Kelly proving how serious the Guardian caps are taken now.

For fans, it could result in seeing more players on the field.

“You know what? I can't say it's the reason why, but we have not had a rash of concussions,” said Riley. “To manage that, not having two a days, guys learning to play with their head up and play safe, but are these having an effect? They darn sure haven't hurt.”

The only question left: Are these protective helmet covers eventually going to make it to the football field on gamedays?