NORMAN, Okla. -- Oklahoma players are warned before the first images begin to flicker on the screen in the defensive meeting room. What they are about to see could be surprising, if not shocking.

But new Sooners defensive coordinator Alex Grinch made clear the undersized, slower players that his players are about to view are for teaching purposes only.

"They're two stars," nickelback Brendan Radley-Hiles said.

"Kids running to the football that weren't even half as talented as we are," cornerback Trey Brown said.

In the early days of Grinch's remake of an epically bad OU defense, it makes total sense to start at the bottom.

That's why, to get his point across, Grinch routinely shows film of his old defenses at Washington State. It's his work there under Mike Leach that has mainly defined him as one of the best young defensive minds in the country.

At age 34, Grinch took over a Washington State unit that in 2015 that had been 99th in the country in total defense, second-to-last nationally against the pass.

Three years later, those supposed talent-deficient, two-star Cougars were kicking butt. Grinch was coaching a top-20 defense, second only to Washington in the Pac-12.

"He even said, 'Those are guys that aren't as highly recruited [as we are] who honestly aren't as athletic as we are,'" linebacker Caleb Kelly said. "Carrying it over, it should be easy for us is what he is saying."

If it were only that … easy. Oklahoma is coming off one of its worst three-year defensive runs in its history -- more than 6 yards per play, 12,400 total yards and 155 touchdowns allowed since 2016. In 2018, the unit was last defensively in the Big 12, which is hard to do. In each of the last two seasons, the defense may have kept the Sooners from national championships.

Two seasons ago, Oklahoma led by 17 in the College Football Playoff semifinal; its offense scored 48 points, and the Sooners still lost in overtime. Last season, the lowest-ranked defense to play for a championship in the BCS era (since 1998) was good enough to be a part of another Big 12 title but folded against Alabama in CFP semis.

Few were surprised. OU may have never been more out of balance between offense and defense. In 2018, Mike Stoops was finally fired after his defense gave up 48 to Texas in the Red River Rivalry. Defensive line coach Ruffin McNeill took over and the unit actually got worse, surrendering at least 40 points in four consecutive games.

Just think about how things could have been different with even an average defense playing with back-to-back Heisman Trophy winners at quarterback.

"You can't say it'll get fixed on its own," Grinch said after spring practice kicked off last week. "The players don't know you. You don't know them. At the expense of being a nag, it's a constant not letting guys get away with anything on the football field."

This is where that Washington State film comes in. Creating those turnovers is mainly how Grinch's 2017 unit in Pullman rose to No. 16 in total defense. The Cougars finished in the top 10 with 28 turnovers. There were 75 takeaways in Grinch's three seasons with Wazzu -- an average of one every 35 snaps.

Here's what makes a great marriage: Only four teams had fewer takeaways than OU last season. Those 11 turnovers gained were the fewest in program history.

Grinch isn't the first coach to stress the importance of turnovers. He is one of the more unique in getting it done.

"Everything we do is with that in mind," Grinch said. "In basketball, you're not confused. 'Go get the ball.' In baseball, the ball is hit to you. 'Go get it.' In football for some reason coaches are guilty of, 'Keep the ball in front us.' That's No. 1A; 1B is to get it."

So Oklahoma's defense will attack, something critics might say it hasn't done in years. Grinch's defenders are taught to run across the field to strip the ball whether it is right there or half a field away -- whether it's in shorts, pads, scrimmages or full-go drills.

After each practice, high achievers are rewarded for their ability to create turnovers with candy bars -- specifically Payday bars.

"It's all we talk about -- every single play," Grinch said. "We're stripping the ball, fighting for the football. It's the top goal. We make it a big-ass deal.[When players succeed], we throw candy bars. We give them gear. The guy who has the most strip attempts is the 'Strip King.' He gets the king-size candy bar."

Not exactly a Turnover Chain, but you get the point. Grinch, 38, is the son a retired Marine. He won three national championships as a defensive back playing for the legendary Larry Kehres at Division III Mount Union.

Grinch has been nominated for the Broyles Award that goes to the nation's top assistant on three occasions. He doesn't particularly like the ancillary attention his defensive approach has caused. During Grinch's run in Pullman, Washington, the term "Speed D" was coined.

"It was not designed to be a hash tag," Grinch said in 2017.

Nevertheless, with Grinch calling the shots, a Leach defense was somewhat proportionate to his Air Raid offense for the first time in the offensive mastermind's career.

It has to get better at Oklahoma because it can't get much worse. There were times in that Georgia game 14 months ago when a sportswriter's untrained eye could tell the Sooners weren't even lining up right.

"What's different about this guy is effort," OU cornerback Tre Brown said of Grinch. "It's not about the call; it's how you play it. If you don't bring effort, nothing is going to really work. We need energy."

This does not ignore last season at Ohio State where Grinch was co-coordinator. But Greg Schiano called the plays for what ended up being the worst Buckeyes defense in history (more than 400 yards allowed per game).

Back in charge of a defense, Grinch can rely on his -- sort of -- algorithm. He says the numbers prove that getting at least 24 turnovers per season equals at least nine wins. In his three seasons with the Cougars, they averaged 24.3 turnovers and won 26, just short of nine wins per year.

"If there is any place you could clearly see what works, you go to a place like Washington State," former Missouri coach Gary Pinkel said. "And I hate Washington State. I'm a Husky."

Pinkel gave Grinch his big chance, hiring him first as a graduate assistant at Mizzou in 2002 and then as his safeties coach in 2012. (Earlier in his career, Pinkel spent seven of his 12 years at Washington as Don James' offensive coordinator.)

Pinkel is also Grinch's uncle.

"At the end of the day, you don't have to have the best players to improve dramatically," Pinkel said. "It's not just, 'Tackle and get the ball out.' Oklahoma will also start getting great, great players because they want to be part of the defense."

Missouri's retired coach initially agonized over hiring his nephew because of how it might look. But Grinch's talent proved his uncle wise. When Leach needed a new defensive coordinator, he found Grinch by watching Missouri's safeties on film.

In Grinch's three seasons, Missouri led the SEC in fumble recoveries (41).

"It's a part of our DNA," said Roy Manning, Oklahoma's cornerbacks coach who was with Grinch at Washington State. "It's a part of what we do. … It's reinforcement that it matters when you strip the football. It matters when it's just an attempt and you sprint 20 yards to go get that football. It's funny how lucky guys get when they're running to the football."

That cornerback, Trey Brown, was certainly feeling fortunate coming off the field after his first Grinch-led spring practice.

"Hopefully, I can get a candy bar," he said. "I did get a turnover today."