MIAMI GARDENS, Fla. -- If anybody on the Oklahoma offense did not personally need to see change from 2014 to 2015, it was Samaje Perine.

As a freshman, Perine emerged as the Sooners' top running back, breaking out with 1,713 yards and 21 touchdowns. He set the FBS single-game rushing record with 427 yards against Kansas, and even in Oklahoma's devastating 40-6 defeat to Clemson in the Russell Athletic Bowl, he still rushed 23 times for 134 yards against arguably the nation's best defense. Oklahoma went 8-5, but the running game might have been the last thing that needed a new approach.

Changing the running game became a byproduct of necessary big-picture changes. Head coach Bob Stoops fired co-offensive coordinators Josh Heupel and Jay Norvell, who Perine thrived under, and brought in East Carolina offensive coordinator Lincoln Riley, a pass-happy Air Raid disciple of Mike Leach at Texas Tech. If anybody was to be negatively impacted by the new direction of the offense, it was Perine, who also would have to deal with the eligibility of former five-star recruit Joe Mixon, who was removed from the team in 2014. Last year at East Carolina, Riley's offense ranked 106th in rush attempts per game.

Despite the change, and despite a disappointing first half of the season that has left his overall numbers short of 2014, Perine has re-emerged as one of the nation's best running backs, helping to fuel the Sooners' rise to the College Football Playoff and Thursday's Orange Bowl against Clemson. Yes, quarterback Baker Mayfield -- who finished fourth in the Heisman Trophy race -- has proven to be the biggest difference-marker in this offense, but Perine has settled into the new system, proving to be a valuable asset for Riley.

"Just incredibly unselfish," Riley said of Perine. "No ego for a guy that's accomplished the things that he has. And then the flip side of that was how willing he was to buy into to what we were going to do offensively, to work on some parts of his game that needed improving on -- to become a good receiver out of the backfield, to become a good pass protector, to understand this new offense. He was as willing as a true freshman coming in here that never played a snap. All those things combined with the talent he has are what makes him the player that he is."

The 5-foot-10, 230-pound Perine eclipsed 100 yards only once in the first six games, posting 152 yards against Tulsa's lackluster defense. He was given only 10 carries for 36 yards in the upset loss to Texas, in a game in which a revamped offensive line struggled, and he averaged only 3.4 yards per carry in the comeback win at Tennessee. The biggest fears about Perine in the new offense were starting to be confirmed.

Now, however, six of Perine's seven highest rushing totals have come in the second half of the season. He had 185 yards on 24 carries total between the two blowout wins over overmatched Kansas and Iowa State, and he put up 201 on Texas Tech. In Oklahoma's three biggest games of the season, against ranked conference opponents, with the Big 12 on the line, Perine racked up 166 yards against Baylor, 188 against TCU (in a game in which Mayfield missed the second half with an injury) and 131 against Oklahoma State.

Despite the slow start, and despite splitting time with Mixon, Perine has 211 carries for 1,291 yards and 15 touchdowns, averaging 6.2 yards per carry and continuing a phenomenal start to his career in which he has amassed over 3,000 yards in 25 games.

"He's just gotten more comfortable, kind of like all of our guys, with what we're doing schematically," Riley said. "The first half was still just the first half of our first year here, and he's a guy, with the way he runs and all that, that you don't do a ton live with a guy like that in practices. There's not a whole lot to glean from it. I think it took a little bit for him to settle in. We started playing a little better up front. That group kind of gelled. We were so close the first half of the season, we knew were really close to pushing it over the top. When we finally did, the group got some continuity, they got some confidence, and they really took off."

The development along the offensive line has allowed Oklahoma to grow into one of the most complete offenses in the country under the direction of the 32-year-old Riley, who is a rising star in the coaching world. The Sooners rank eighth nationally in yards per play and second in passer rating, and despite Mayfield's Heisman campaign at quarterback and Riley's history in pass-first offenses, the Sooners run the ball more than they throw it. Part of that is Mayfield's penchant for scrambling, part of it is Mixon's value and part of it is the ability of Perine to carry the offense when needed as the team's workhorse.

Stoops, who has a defensive background, takes a hands-off approach to offense, and has, for the most part, let Riley install the offense as he sees fit, while reminding him of the talent in the backfield at his disposal.

"I let him come to terms with it as we evolved in the fourth, fifth game of the year, that look, even in the Texas game, if you look at -- if you take Baker's scrambles or sacks out of it, backs still ran the ball for about four or four-and-a-half yards a play," Stoops said. "So we had talked just a little bit about that, of possibly let's just keep making sure that's strong part of what we're doing, as long as it fits in what you're trying to do. It started to come to fruition after that, and then he wanted to settle on simplifying substitution patterns and just eventually start getting into different formations without substituting, and that helped, as well. He made the adjustments, and again, I've given him free rein."

Stoops said that the offense needed a few games to gel, whether it was growth along the offensive line or Riley getting more comfortable with combinations of players. Once that happened, Oklahoma has been able to push the tempo more often.

While Riley has free rein, other coaches speak of him as collaborative and willing to learn. Perine also dealt with a position coach change this offseason, as 2014 running backs coach Cale Gundy was shifted to a new role, with fullbacks/tight ends coach Jay Boulware taking over the backfield as part of the staff shuffle.

"[Riley] does a great job of giving me ownership and not just saying, 'Hey this is my offense, this is what I run,'" Boulware said. "He's open to learning different things, which I think is a reason why his version of the Air Raid offense features a run game, more so than where he learned from, which almost has no running game."

Until this season, Riley had never been part of an offense that had a running game ranked in the top 60 nationally. His mentor, Mike Leach, still shows little interest in running at Washington State, who ranks last nationally in rushing yards per game. Some of Leach's disciples have branched out, though. Oklahoma ranks 15th in rushing, one spot behind Riley's fellow former Leach assistant, Dana Holgorsen, who has committed to the run at West Virginia.

When Stoops took the Oklahoma job in 1999, he brought in Leach as his offensive coordinator. The marriage lasted only one year, as Texas Tech hired Leach to be its head coach. The Stoops/Riley partnership might not quite be a one-and-done, but Riley's success in adapting the Air Raid to revitalize the Oklahoma offense, with Mayfield and Perine at the center, will likely insure that he'll be a hot name on the coaching carousel a year from now.

Of course, Riley would be foolish not to take advantage of Perine, who combines a punishing style with breakaway speed. Boulware said that Oklahoma runs just about every possible scheme for a running back, and Perine has proven to be an NFL-type talent, especially as he has focused on improving in the passing game since Riley arrived.

Boulware says that what stands out the most about Perine is the way he runs low to the ground at full speed, generating momentum and making him even harder to tackle -- something that first stood out to him in "blaster" drills in practice.

"There's just so many different things you can learn from that, but when Samaje goes through it it's different than all the other guys I have, because he's running full speed but he gets about this low going through it, and I had never seen anybody do it," Boulware said. "That's why he's able to break so many tackles and get underneath people who are trying to tackle him. Not only is he powerful, but he's also flexible, so when I saw that, I said that's special."

Perine is talented enough to thrive in any scheme, and in this case, the way Oklahoma spreads the field, and the way Mayfield keeps defenses off-balance, provides a perfect opportunity for Perine's power to take advantage up the middle. Clemson has another great defense, but on Thursday it will be forced to account for the long list of ways that Oklahoma can create and exploit favorable matchups.

Air Raid typically means pass, and Oklahoma can certainly do that well. But while Mayfield may be getting most of the headlines as the centerpiece of Riley's offense, even in the new system, Perine has become as essential to the Sooners as ever.

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Contact Matt at matt.brown5082@gmail.com and follow him on Twitter @MattBrownCFB and Facebook.

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