Buckle up for what should be one of the defining weekends of the college football season.

A handful of critical matchups loom across the country, including the night game in Norman between Oklahoma and TCU. The winner could very well find itself ranked among the top four when the new College Football Playoff rankings are released Tuesday night.

This much is certain: After this weekend, we’ll be down to one -- only one -- viable playoff candidate from the Big 12.

Here’s what you will be talking about on Monday:

1) TCU’s defense is good, but how good?

Gary Patterson loves a challenge like this, and it’s quite a challenge. TCU ranks first nationally against the run, and sixth nationally in scoring defense and total defense. Plus, he has a veteran unit.

That’s great, but here comes an Oklahoma offense that amassed 785 yards last week against Oklahoma State. Baker Mayfield passed for a school-record 598 yards. Slowing down the Sooners may mean holding them to fewer than 35 points.

Do you trust TCU quarterback Kenny Hill enough to think the Horned Frogs can keep pace with Oklahoma offensively? Not so sure.

2) Which outcome could help the Big 12 the most?

Clearly it would be if Miami could beat Notre Dame in South Florida. The Hurricanes would rise in the rankings, but the Fighting Irish, currently at No. 3 in the CFP rankings, would be eliminated with their second loss. The ACC – presumably Clemson or Miami will win the title – is competing for only one CFP slot (at most), so it would open the door for the Oklahoma-TCU winner to slide right into the top four if it could win out.

If Auburn can beat Georgia, that’s another outcome that could help the Big 12 ultimately if it could reduce the SEC’s playoff berths to just one. But it will take a few more weeks to see if that can transpire.

3) Is Iowa State’s remarkable run over?

The Cyclones, who had beaten two top-five teams last month, fell behind early at West Virginia last week and never fully recovered.

Iowa State should be able to move the ball through the air with receivers who have a height advantage over Oklahoma State’s defensive backs. The problem is trying to stop Oklahoma State’s big-play offense.

Regardless of the effectiveness of receiver James Washington, who is nursing an ankle injury, the Cowboys have plenty of weapons beyond Mason Rudolph, who leads the league with 3,314 passing yards. Running back Justice Hill is the league’s leading rusher.

4) Has Texas Tech recovered from last week?

The Red Raiders suffered a disheartening loss to Kansas State at home last week. Now they must regroup to play a Baylor team with nothing to lose at a neutral site in Arlington.

If Tech shows any emotional hangover from last week, expect Baylor to capitalize. To say the Red Raiders have regressed the last few weeks is an understatement. They have struggled mightily on third down defensively, and thus have lost four straight games. This is a must-win contest.

5) Will Kansas score a point?

Unless the Jayhawks can cause havoc with their special teams or defense, they will have a tough time scoring any points against Texas.

The Longhorns contained Oklahoma State in 13-10 overtime loss. And after beating the Longhorns, TCU’s Patterson felt they were just about as physical of a team that they had played all season.

Kansas has not won a road game since 2009. Don't expect that streak to end here.

Eric Prisbell covers the Big 12 for CNHI Sports. Follow him on Twitter at @EricPrisbell and email him at eprisbell@cnhi.com.

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