Free Throw - Resumption of Play

[BLS]

Is there a rule or case number that determines when the violation is called when the ball is placed on the floor during resumption of play for a free throw?

NevadaRef indicates the violation is not called until the free thrower actually enters the semi-circle, or the 10 second count is reached. Team A could call a TO to avoid the violation.

Can someone point me to the rule or case to support that? I can only find 9.3.e which says the the free thrower can't be outside the semi-circle after the ball is at the disposal of the free thrower. Isn't the ball at disposal when the ball is placed on the floor, which means a violation immediately?

Thanks!