Ash, 24, had ended his playing career in September 2014 after struggling with symptoms as a result of multiple concussions. The school confirmed Thursday he has been cleared to play and will participate in Texas' pro day on March 28.
In addition to throwing at the pro day, Ash will also audition as a punter, a school spokesperson confirmed. He was a first-team all-state punter as a senior at Belton High School in Belton, Texas, in 2010.
Ash first suffered a concussion in a September 2013 loss to BYU. He suffered another concussion in the 2014 season opener -- just his second game after the first concussion -- and decided soon after to stop playing.
"I'm at peace with that. God has given me a peace," Ash said when he announced his retirement. "I have a lot of hope and a lot of belief that there's still awesome days ahead for me."
Ash threw for 4,728 yards and 31 touchdowns and went 15-7 as a starter during his four seasons at Texas.
He is not the only former Texas quarterback attempting a comeback this spring. Vince Young signed with the Saskatchewan Roughriders of the Canadian Football League last week. He last played in an NFL regular-season game in 2011 and had retired in 2014