QB David Ash (Jr.)

For the first time in his career, Ash came into this season as the unquestioned starting quarterback. It took a concussion in the fourth quarter of Texas’ loss to BYU to knock Ash off the top of the depth chart. He returned two weeks later against Kansas State, only to be knocked out with yet another head injury. Ash needs a week between when he’s medically cleared and when he can suit up again. He can get a medical redshirt if he’s not cleared by season’s end. 

RB Johnathan Gray (Jr.) 

Gray was on his way toward turning in the first 1,000-yard season by a Texas running back since Jamaal Charles in 2007 before rupturing his right Achilles tendon last week. Losing Gray is a big blow to a Longhorns offense that relies on their running game so much but backups Malcolm Brown and Joe Bergeron are more than capable of picking up the slack.

OG Mason Walters (Sr.) 

Walters was a game-time decision before Texas’ Big 12 opener against Kansas State with a knee injury. He started in that game and has started every game since. In fact, Walters has started each of Texas’ 47 games over the last four seasons. He is considering having postseason surgery to repair his knee but, for now, Walters is playing through the pain. 

OT Josh Cochran (Jr.) 

Cochran missed spring practice with a fractured leg but, after starting all 13 games last year, started the first three games year… before sustaining a shoulder injury that has kept him out of the last six games. He is out again this week against Oklahoma State. 

OT Kennedy Estelle (So.)

Estelle was the highest-rated offensive line prospect to sign with Texas before last season and has filled in admirably for Cochran in the each of the last six games. But he went down with a hip injury against West Virginia and fellow sophomore Sedrick Flowers replaced him for the second half. Co-offensive coordinator Major Applewhite indicated Tuesday that Estelle should be ready to go this week.

DT Chris Whaley (Sr.)

Whaley became the heart and soul of this Texas defense over the last few weeks, scoring key touchdowns against Oklahoma and Kansas while constantly finding his way into opposing backfields. But he was carted off the field in the first quarter of last week’s win after suffering a season-ending knee injury. Desmond Jackson quickly picked up two sacks and a forced fumble in Whaley’s place but even Jackson admitted that Whaley is irreplaceable. 

LB Jordan Hicks (Jr.)

Hicks missed the final 10 games of the 2012 season with a hip injury, earning him a medical redshirt before this season, only to be knocked out for the rest of the season with a torn Achilles four games into this year. The Texas defense has adjusted much better to his absence this season than it did last year, but Hicks has still been sorely missed. 

LB Tevin Jackson (Jr.)

Jackson has played in nearly every game since coming to Texas in 2011 but didn’t crack the starting lineup until last season, starting the final two games of the year against Kansas State and Oregon State, making a career-high seven tackles in the Alamo Bowl win over the Beavers. But he suffered a torn left ACL in the win over Kansas two weekends ago and is also out for the season.