The signing came two days before the Hawks play their final preseason game, against the Miami Heat on Thursday in Atlanta. They open the regular season Oct. 21 at home against the Minnesota Timberwolves.
Watson went undrafted in June and signed with the Hawks in July before the start of the NBA Summer League in Las Vegas, Nev., where he averaged 4.4 points in 16.6 minutes per game.
Watson played his first two seasons at Michigan and averaged 12.5 points in two seasons at Dayton.
Like his former teammate Jalen Crutcher, who signed with the Charlotte Hornets last week, Watson likely will play in the NBA G League this season. The Hawks’ affiliate is the College Park Skyhawks. The Hornets’ G League team is the Greensboro Swarm.