Oklahoma is easily the favorite popular choice to repeat as Big 12 champions in 2016 after they re-established themselves on the throne in 2015. Everything went right last year for the Sooners, they were able to plug in the ultimate "chip on his shoulder guy" Texan at QB, their 3-4 defense finally came together, and they were extraordinarily lucky with opposing injuries, regularly facing the top Big 12 teams' 2nd string QBs.
Repeating the feat in 2016 will require that the Sooners are able to reconfigure their schematic formulas on offense and defense to make up for the departure of a pair of small but dominant athletes in WR Sterling Shepard and SOLB Eric Striker.
Striker was a huge part of the Sooner pass-rush in 2015 and had seven sacks of his own while also setting up teammates for favorable pass-rushing match-ups with the threat he posed coming off the edge or even looping inside. The Sooners will be looking to try and replace Striker with more nickel packages and some up and coming pass-rushers, prognosis here is uncertain.
Replacing Shepard should be a bit more straightforward, but the hole he's leaving behind is not inconsiderable.
2015's go to guy
Shepard wasn't huge, only 5'10" 195, but he caught 86 balls over the course of the year for 1288 yards and 11 TDs. Besides his endurance, the particular brilliance of Shepard was how effective he was running a variety of different routes both from the outside or inside in the slot.
When Oklahoma wanted to take the top off a defense, Shepard was the guy they'd use. On the outside they'd just run him on go routes, sometimes with a comeback option so that Mayfield could find him when he had to scramble...which was all too often in 2015 and will likely be less often in 2016 with both young tackles returning.
OC Lincoln Riley was also clever about getting Shepard in position to attack safeties deep, especially with seven routes (deep outs) that he could run on either safety from the slot.
When the Sooners wanted to get after a weak safety they'd run smash or snag on the boundary with Shepard running the seven route potentially isolated against the safety:
When they wanted to get after the field safety the Sooners would mix in a seven-in-in combination that was useful for attacking trips coverages:
Oklahoma could line up Shepard in either trips slot position based on which was would be able to cut outside into open grass against the deep safety. Against most defensive responses that would look like this illustration above.
Shepard's reliable hands and darting route breaks made him lethal on most routes, the seven was just one of OU's favorite ways to use him for exploiting safeties.
The question that had to be begged during Oklahoma's fantastic year on offense in 2015 was whether they'd always feature Shepard because they lacked other options, or because they could? Opposing defenses couldn't control Shepard, especially given the way that Riley could move him around based on their opponents and match-ups.
We caught a glimpse of what a post-Shepard Sooner offense might look like though when they faced Clemson in the playoffs.
Practice in the playoffs
The ace up Clemson's sleeve was Mackensie Alexander, a lockdown corner who understood the Tiger defense well enough to be able to play outside or inside over the slot if they wanted him to shadow an opposing WR. Alexander didn't shadow Shepard for the entire game, nor did he or the Clemson defense lock him down, but the Sooners definitely explored other passing options in that game out of a search for simpler targets.
As a result, it was revealed that OU has some other weapons that could play a big role in 2016 with just a little seasoning and focus within the offense.
The best thing the Sooners have going for them is their backfield, where they return their three-headed Cerberus of Baker Mayfield, Joe Mixon, and Samaje Perine. Those three were very effective in the run game last year for OU:
Besides the fact that all three of these guys are effective runners and will return with an OL that's even more proficient in Riley's new schemes (counter-trey is now a huge part of the OU arsenal), Perine and Mixon were also effective in the passing game.
Perine has always been solid and posted 15 catches for 107 yards and a single TD last year while Mixon split time as a slotback and caught 28 balls for 356 yards and four TDs. Oklahoma should have an easy time leveraging the threat each can present running routes underneath to create windows to hit receivers downfield.
Against Clemson they did a lot of damage with the slant/flat combo, in this instance running it to the boundary opposite a "snag" combo with Mixon and Perine each running flat routes out of the backfield:
When your backs can do things like this...
...running simple underneath routes then it tends to open up opportunities for your receivers to find leverage downfield.
Another likely part of the effort to replace Shepard's production will be young flex TE Mark Andrews, who might be capable of taking on some of the 3rd down targets that Shepard took up in 2015.
At 6'6" 247, Andrews is a match-up nightmare running routes in the seams and he has some quickness and power after the catch as well.
One of the biggest questions for Oklahoma in 2016 will be whether Andrews can take on some of Shepard's load running seven routes, digs, and slants in the middle of the field so that Mayfield can continue to attack the league's safeties and have a reliable 3rd down target.
If Andrews isn't the answer there then OU will have to find another one and his role in the offense will be somewhat blunted because they need those components to make their system work.
As far as deep threats go, OU's leading returning receiver Dede Westbrook has a ton of potential so long as his recent off-field issues don't present an obstacle to him capitalizing on it.
Because they're returning an amazing backfield and top-flight QB, both offensive tackles, and some very promising WR talent that was waiting in the wings while Shepard did his thing it's reasonable to conclude that the Sooners will again be very potent on offense in 2016.
So long as they can replace Striker, they'll be a good bet to repeat as league champs if not a playoff contestant.