held ball or foul

[ysong]

I need some help with a question about "unreasonable" steal:

after a player gets a defensive rebound, he holds the ball firmly against his chest with two hands (or arms), he also coils his uper body a little bit to protect the ball. while the player is looking for an outlay pass, an opponent, disregarding the fact that he is "from a position from which he/she has no reasonable chance to play the ball without making contact with the opponent", still try to rob the ball from the ball holder, even though without significant body contact initially. But when both players strugle for the ball, significant body contact occurs.

in this situation, what call is preferred, held ball or a personal foul? if a foul call is preferred, when should the call be made, at the moment the opponent contacts the ball holder (even though it is minor), or only when severe body contact occurs?

Thanks.