Oklahoma is road tested, with losses at USC and Memphis; they handled TCU at home by 28 last year and should cover this small spot.
I also second copperblue's selection of the under, adding the stats below. Oklahoma should play with intensity with two Ls already on their record.

STRENGTH/SIDE: 4* / OKLAHOMA -4 (-110)
Horned Frogs are 7-20 ATS in their last 27 games as a home underdog of 0.5-6.5.
Horned Frogs are 2-6 ATS in their last 8 non-conference games.
Horned Frogs are 3-9 ATS in their last 12 games vs. a team with a winning % above .600.

STRENGTH/TOTAL 3* OK/TCU UNDER 131.5 (-110)
Under is 14-4 in Sooners last 18 games as a favorite.
Under is 9-4 in Sooners last 13 games following a ATS loss.
Under is 40-19 in Sooners last 59 non-conference games.
Under is 26-9 in Horned Frogs last 35 non-conference games.

GL to all