FED case book 8.3.2 Situations C and I add a very interesting word to the case... they say that a fielder is allowed to be in the path if the play is "Imminent". Once the ball is past, there is no more imminence. Imminence refers to things in the future.
I still think whether he was making a play, whether he had a chance to avoid contact, etc... makes all of these kinds of things a HTBT, but I figured I'd stir the pot a bit.
Lee