An erratic, turnover-filled start by sophomore David Ash in a 20-13 Thanksgiving night loss to TCU added fuel to a simmering quarterback controversy at Texas.

Coach Mack Brown isn’t keeping his starting quarterback a mystery preparing for Kansas State on Saturday. He announced Case McCoy will start, while Ash is listed as questionable with a rib injury.

Mack Brown also says Case McCoy will start for Texas at K-State this weekend. Ash is questionable with his rib injury.—
David Ubben (@davidubben) November 26, 2012

Mack Brown on David Ash: "He got hit in the ribs early in the game and didn't tell us. That probably led to some of his struggles."—
David Ubben (@davidubben) November 26, 2012

McCoy relieved Ash late in the first half against TCU after the Texas starter threw two interceptions in the red zone and fumbled the ball away inside his own 20.

McCoy, a junior, has completed 28 of 42 for 408 yards, 4 touchdowns and an interception in eight games in 2012.

Citing an unidentified source, Bobby Burton of Hookem.com, the 247Sports site that covers Texas, is reporting that sophomore David Ash will start the Longhorns’ season opener against Wyoming on Sept. 1. (The site’s partner, the Austin American Statesman, has details on its website.)

Coach Mack Brown has yet to publicly name his choice, but offensive co-coordinator Bryan Harsin said on Monday that both Ash and junior Case McCoy would take snaps against the Cowboys.

Ash started six games in 2011 and was named offensive MVP of the Holiday Bowl. He played in all 13 contests. McCoy started five times and had a better completion percentage, nearly as many passing yards, and a significantly better TD-interception ratio than Ash. (Garrett Gilbert, who has transferred to SMU, started the first two games of the season.)