Prior to the 2019 NBA draft, Alston worked out with the hometown Philadelphia 76ers. He competed for the Indiana Pacers in NBA Summer League play and averaged 8.0 points per game. On October 19, the 76ers signed and waived Alston so they could add him to their G League affiliate, the Delaware Blue Coats. He averaged 3.7 points, 2.9 assists, and 1.8 rebounds per game in 23 games.