[UmpJM]

Paul L.,

#1. It depends on where the runners are. For purposes of illustration, let's say the bases are full and a RHP.

If that is the case, once the RHP moves his free foot in a direction other than directly to 1B, he can no longer go to 1B, or he will have balked; he may still throw a pick-off to 3B or 2B or deliver a pitch.

As he lifts his stride leg to balance and and pivots his body, if his free foot passes the back plane of the rubber (partially in OBR, completely in FED), he has lost the option of going to 3B, but may still throw to 2B or deliver the pitch.

Once his body momentum "reverses" so that something is moving back towards home (shoulder, foot, leg...) he must now deliver the pitch.

Unless he never "broke" the back plane of the rubber. If he did not, he would still have the option of throwing to 3B as long as he "lands" his free foot more in the direction of 3B than to 2B or home, and does so before releasing the throw.

#2. I believe his pivot foot must land entirely behind the rubber for it to be a legal disengage.

JM