NORMAN, Okla. -- Not long after Bob Stoops won a national championship in his second season at Oklahoma, the Cleveland Browns tried to pry him away.

In his words then, Stoops had "always been intrigued" by the NFL. And so he did listen to the Browns. But ultimately, Stoops opted to remain in college. And in the end, exclusively with the Sooners.

Nearly two decades later, Stoops' successor at Oklahoma, 35-year-old Lincoln Riley, is about to arrive at a similar crossroads. Time will tell whether Riley's second season with the Sooners will also end, like Stoops' did, with a national title. But regardless of what happens with Oklahoma on Dec. 29 in the College Football Playoff semifinal at the Capital One Orange Bowl against No. 1 Alabama, Riley figures to be a hot commodity when the NFL coaching carousel begins to spin.

The Browns have an opening again after firing Hue Jackson last month -- and their franchise quarterback is Baker Mayfield, who won the Heisman Trophy under Riley at Oklahoma. Speculation on Riley taking over the Browns is so rampant in Cleveland that Mayfield was actually asked Wednesday about his former coach potentially making a move to the NFL.

"Lincoln's been ready," Mayfield said, when asked whether Riley could make the successful transition to pro football. "Just who he is, how he coaches, the respect level he's had from all of his players. How detailed he is. He's ready.

"But that's his decision. He's got something special there. I don't think anybody's going to blame him if he stays there for the next 20 years."

Baker Mayfield believes Lincoln Riley could succeed in the NFL right away. AP Photo/Sue Ogrocki

Riley indeed has something special working at Oklahoma.

In two seasons with Riley as head coach, the Sooners have led the country in both total offense and offensive efficiency. The two years before, with him calling plays under Stoops, Oklahoma ranked in the top four in college football in scoring.

After losing Mayfield, who was the No. 1 overall pick in the NFL draft, along with several other key starters, Oklahoma seemed destined for a dip offensively this season.

Instead, the Sooners have remarkably been even more lethal on the way to their third playoff appearance in four years, posting the highest offensive efficiency rating (96.6) since ESPN began tracking the data in 2005. On top of that, quarterback Kyler Murray owns the highest QBR (96.0) going into a bowl of any FBS player since ESPN starting using the metric in 2004. This weekend as a result, Murray could give Oklahoma the first back-to-back Heisman-winning quarterbacks of any school in the history of the award.

Such virtually unprecedented level of production with two quarterbacks boasting different skill sets and fairly different personalities has caught the eye of NFL executives. And Riley's imagination intrigues the the league's coaches.

While evaluating Mayfield and all the Oklahoma talent, NFL evaluators thoroughly praised the creativity of Head Coach/Play Caller Lincoln Riley. Oklahoma has become one of the top destinations for NFL coaches to learn from. Nearly all 32 teams have come through Norman to learn. — Chris Mortensen (@mortreport) April 27, 2018

"If you're an NFL team and you're looking for a head coach and (Riley) says, 'I'm out there, call me.' ... he'll be No. 1 on their list," one NFL scout said. "With the success he's had there so far, not only with the offense that he has and the numbers he's put up, but those players, specifically Baker, that have come into the league and played well. ... I assume he'd be a lot of people's first call, when he decides to make that choice."

Riley's own success with the Sooners isn't the only reason why. Versions of the Air Raid offense Riley honed while working under Mike Leach at Texas Tech have already begun thriving around the NFL.

"The NFL game is certainly trending more toward what you see on Saturdays for a lot of different reasons," Riley said late last month. "The games look a lot closer than they did five years ago, without a doubt."

That is occurring most notably in Kansas City, where Air Raid alum Patrick Mahomes leads the NFL with 41 touchdown passes -- nine more than any other quarterback.

Lincoln Riley's version of the Air Raid offense, once considered a gimmick before making a huge impact in college football, is now en vogue in the pros. Brett Deering/Getty Images

"That's where our game is going," the scout said. "Guys in the Air Raid and all those systems that were looked down upon as gimmick offenses before, that's where we are now. And those are the guys that are going to be in the league"

Sean McVay, meanwhile, is proving that age is just a number when it comes to coaching in the NFL. Three years younger than Riley, McVay, also regarded as an offensive guru, has powered the Los Angeles Rams to the best record in the league.

"The more guys like Sean McVay win, the age thing is kind of slowly going away. You see the energy the Rams have, the passion, how guys play for a guy like Sean McVay, I think people are energized by that," said the scout, who noted Riley's biggest obstacle would be hiring an NFL staff and finding an experienced, proven coordinator, like the Rams' Wade Phillips, to run the defense. "And Lincoln has always struck me as a guy that was just mature beyond his years."

All meaning the overriding question could be less about whether the NFL is ready for Riley -- and more about whether Riley is ready for the NFL.

"You sit here and answer these questions and I always want to be truthful," Riley said on the same day the Browns job came open last month. "The truth is for me is I love Oklahoma. I love coaching here. I love college football. I certainly don't have that itch right now. Don't know that I ever will.

"But I'm never going to be a guy that stands up here and says no way, no how, with any of these things ever happening. I don't know that."

Before the Big 12 championship game, Riley was pressed to expound on specifically what he loves about coaching at Oklahoma and what he loves about coaching college football.

"I like the age, the guys I'm coaching. Still kind of in that 'hot zone' where they're still growing. They're kind of learning to become men at this point but there's a lot of growth that's gotta happen in these years. I enjoy that part," Riley said. "I enjoy the X's and O's, but I do enjoy at this level the different hats you have to wear, especially in this role as a head coach. I enjoy getting out and recruiting. I enjoy talking to these guys about their academics, about things going on in their lives you don't necessarily have at other levels. There's just a lot more going on, a lot more growth, a lot more things that are going to shape the rest of their lives and it's kind of all yet to be determined for these guys. Kind of like being a part of this process with them. I like the vibe of college ball, I do. The way it's set up, the rivalries. I just think the sport's in such a good place right now, I do. I love that part of it. I always have."

And Oklahoma?

Kyler Murray has a different style than Baker Mayfield, but Riley tailored the offense to him and Murray has a chance to give Oklahoma back-to-back Heismans. Kevin Jairaj/USA TODAY Sports

"I love that fact that we're invested here. I love the fact that we have what we need to be successful," he said. "I love the fact that people care about our program, [which] has been nationally relevant for a long time. People here are invested in it, that the former players come back. I know how much it means to this community, to this state. ... To coach football at any level, anywhere, this is absolutely one of the elite programs, regardless of level, without a doubt.

"There's not a better job anywhere else."

Barry Switzer, who won three national championships with the Sooners before later winning a Super Bowl with the Dallas Cowboys, certainly agrees.

@LincolnRiley I told Bob when mentioned for NFL job's! "More coaches would want the job you just left than one you just took" @OU_Football — Barry Switzer (@Barry_Switzer) October 30, 2018

"There would be a hell of a lot of NFL coaches who'd rather coach at Oklahoma," Switzer said. "Because at Oklahoma, you're one of the top five schools in the country. Everyone in coaching wants to get to an Oklahoma. The Alabamas, the Ohio States, the Oklahomas, they're the top jobs in the country. Why? Because you can dictate. You can control your destiny. You can win. You can win consistently. You recruit consistently well. They're paid tremendously now. They make a lot more than some of those damned NFL jobs."

Riley is currently making $4.8 million at Oklahoma, plus up to $700K in bonuses. That already would rank middle of the pack in the NFL. Riley, however, has a clause that includes a $100K raise year, meaning Riley will earn roughly an average of $5 million per year through the life of the contract. Despite being at Oklahoma, Riley is still not one of the 15 highest-paid coaches in college football, according to USA Today, though that is sure to change soon after he's put the Sooners back in the playoff.

"Pro football is a suitcase job," said Switzer, referring to the number of times an NFL coach might have to move from job to job. "You think Bob Stoops is going [to] work it the rest of his life? He's made $30-40 million dollars coaching Oklahoma."

Riley already has Stoops-level job security in Norman with big paydays on the horizon. Yet that also doesn't mean he's destined to stay in college for the rest of his career like Stoops, either.

The NFL is ready. It could be a matter of time before Riley is, too.

"I think down the road, probably," Mayfield said. "I'm not going to speak for him.

"But he's ready whenever that time comes."