Brown, who is ranked No. 29 in ESPN's top 100 draft prospects, was a top-10 recruit when he signed with Texas and former coach Shaka Smart. He was projected as a first-round draft pick and few expected him to stay with the Longhorns more than one season.
"I would like to thank the University of Texas for the historical year and all the great memories," Brown said in an Instagram post. "I will cherish them forever."
Brown also said that he had already signed with an agent.
He started 24 games last season and averaged 9.3 points and 6.2 rebounds, but his minutes diminished late in the season. He abruptly left the court after being taken out in the first game of the Big 12 tournament, and played just 12 total minutes in the league championship game and Texas' first-round loss in the NCAA tournament.