With a college postseason invitation not occurring, Mitchell decided to be the first underclassman to declare for the 2013 NBA draft. He was the first North Texas player to be drafted in the NBA since the Dallas Mavericks drafted John Horrocks in 1984. Mitchell was drafted by the Detroit Pistons with the 37th overall pick in the draft. He was also the highest North Texas player to be drafted in the NBA, ahead of Kenneth Lyons in 1983 (47th overall). On July 19, 2013, he signed with the Pistons. When the 2013 rookie class convened for its annual photo shoot and filled out its NBA.com Rookie Survey, the class voted Mitchell as the most athletic.