The Aggies granted his release on Thursday. The school didn't say where Allen would be going.
The sophomore appeared in 10 games for the Aggies this season and threw for 2,210 yards with 17 touchdowns and seven interceptions.
Allen won the starting job out of camp but was benched in favor of freshman Kyler Murray after throwing three interceptions, all of which were returned for touchdowns, in a loss to Alabama in October.
Allen received only sporadic playing time after he was benched. He played in 10 games as a freshman last season after Kenny Hill was benched after his struggles.
Overall, Allen went 9-5 in 14 career starts.