The Grizzlies said Saturday that Rabb would be re-evaluated and the team would update his situation after the first three games.
Rabb, a 6-foot-10 forward from California, sprained his ankle during a pre-draft workout.
Memphis obtained Rabb for a future second-round pick after the Orlando Magic selected him in the second round. Rabb was the 35th overall draft pick.
The 20-year-old Rabb played 31 games for California as a sophomore this past season. He averaged 14 points, 10.5 rebounds, 1.6 assists and 1 block.