Things to watch in the Big 12 in Week 5, the first full weekend of conference play, which got an early start with Kansas playing at Texas Tech on Thursday night:

GAME OF THE WEEK

Oklahoma (1-2) at No. 21 TCU (3-1, 1-0 Big 12). While two September losses have already eliminated any realistic chance for Oklahoma to return to the College Football Playoff for the second year in a row, the Sooners have a clean slate in the Big 12 — they were the overwhelming preseason favorite to win their 10th title in the league. This game features two former transfer quarterbacks: Oklahoma second-year starter Baker Mayfield (from Texas Tech) and first-year TCU starter Kenny Hill (from Texas A&M). Oklahoma has a 3-1 advantage in its Big 12 matchups against the Horned Frogs, but the total combined margin in those games is 15 points.

BEST MATCHUP

OK, most interesting matchup to watch. Texas defense vs. Oklahoma State offense. The 22nd-ranked Longhorns (2-1) will quickly find out the effectiveness of changes made on defense during the open date after giving up 50 points and 396 yards passing in a loss at California . James Washington leads the Big 12 with 122 yards receiving a game, while the Cowboys pass for 340 yards a game. Texas has allowed a Big 12 high-matching nine TDs passing without an interception.

INSIDE THE NUMBERS

Kansas State is 5-0 against West Virginia since the Mountaineers joined the Big 12 Conference. ... Three TCU defensive linemen (Aaron Curry, L.J. Collier and Tipa Galeai) have 2 1/2 sacks each, matching them with Baylor end K.J. Smith for the Big 12 lead. ... Oklahoma hasn't lost back-to-back games since October 1999 in coach Bob Stoops' first season. ... Texas Tech QB Patrick Mahomes has 1,493 yards passing in three games, a total not reached that quickly by any quarterback nationally since at least 2000.

LONG SHOT

Any Big 12 team getting through conference play without a loss . Since the Big 12 became a 10-team league in 2011, there has not been an undefeated champion — each one has had an 8-1 league mark, with two teams sharing the title with that record in 2012 and 2014. Only Baylor and West Virginia went undefeated in nonconference play this month — the fewest for the Big 12 as a 10-team league, after seven teams were without a loss in nonconference play last year.

IMPACT PERFORMER

Baylor senior linebacker Aiavion Edwards, who had 17 tackles in the Russell Athletic Bowl last December, goes into Saturday's game at Iowa State leading the Bears this season with 33 tackles (8.2 per game, second in the Big 12), including 22 solo stops. He had 12 tackles last week against Oklahoma State. He has also squatted 710 pounds, the highest on Baylor's team.

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Compiled by AP Sports Writer Stephen Hawkins in Fort Worth, Texas.

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AP College Football website: www.collegefootball.ap.org