[mcrowder]

Originally Posted by DG

If the catcher is making a play, ie receiving a thrown ball, and the play is imminent, he can block the plate. What is imminent you might say? A rule of thumb is the ball is in flight, directly at the catcher and in the air over the dirt cutout, which should be about 13 feet from the plate. If the catcher was where he needed to be to catch the throw and it was in flight 13 feet from the plate, then I would not rule obstruction. The block, the catch and the tag would have to be bang, bang, bang. It if was block, pause, catch, tag then maybe obstruction is the correct call.

Everything here is true, but there's yet another way this is not OBS. If the blocking occurred too early (earlier than in the quoted post), but the runner did not alter his path, then F2 still did not obstruct. Remember that you have to have two things for obstruction - a fielder in a position that causes a runner to react (assuming no imminent play) AND a runner that actually does react (whether by his own will or by contact).