12-13 active rostered per team, but generally 15 total per team = 450, plus 50 or so journeymen from the D-League
For future reference, in my eyes, Royce White never stepped foot on the floor in a regular season game so therefore he does not count as a ex-Rocket who would be eligible to be discussed in GARM. Plain talk: Royce White related threads go in the Dish, not the GARM.