Roby is out for Thursday's game against the Nets due to a plantar fascia injury in his right foot.
Roby will be sidelined for a fourth consecutive game on account of the injury, but even when healthy, he hasn't been a member of coach Rick Carlisle's rotation. The rookie second-round pick is still awaiting his NBA debut, though he's made five appearances for the Mavericks' G League affiliate, the Texas Legends.