Thornton entered his name into the transfer portal on Friday afternoon, sources told ESPN. He will be immediately eligible to play next season.
Thornton, a five-star recruit coming out of high school in the Class of 2015, began his college career at Duke. He left the Blue Devils after his freshman season, transferring to USC in June 2016. Thornton played a bench role during the 2017-18 season but started 27 games this past season for Andy Enfield's program.
He averaged 7.7 points and 4.3 assists in 2018-19.