Which is not good for David Ash.
Ash originally suffered his concussion in Texas' loss to Brigham Young on September 7. He would miss the next week's game against Ole Miss, but return to the field a few weeks later against Kansas State on September 21. However, Ash would not finish the game due to the effects of his concussion.
He has not played in either of Texas' last two games, meaning it's not been a month and a half and he's still dealing with the concussion. It's enough to make you think it would be better for Ash if Texas just ruled him out for the rest of the season. If the concussion is serious enough to keep him out this long there's really no reason to take any chances.
Case McCoy will continue starting in Ash's place.