[Rich1]

By rule, after a made basket the throw in begins when two things happen - the ball is available to the player and the ref starts the count. There is no mention in the rules about allowing the player to step out of bounds first. This is different than other throw ins because we handle the ball.

Now, in practice, I give a player time to step out if they grab the ball and are not delay in moving out of bounds. I start the count if they do not secure the ball and head that way with purpose.

Using some of the logic cited earlier, then it could be argued that we shouldn't place the ball on the floor and begin a count during the delay of game procedure because if the player isn't out of bounds then we can't start the throw in. Yes, its an absurd stretch, but serves to illustrate that throw ins occur under different circumstances and are officiated that way. (And yes I know the "ROP" procedure is rule, I'm just making a point)

The answer to the question in the OP is you start the count when in your judgement you feel the team has access to the ball and has had time to pick it up and step out of bounds. You do not need to wait until they actually do so.