Runner from 2nd is trying to score on a single, catcher is blocking the plate as the ball is in the infield. is it legal for him to block the plate?

Preventive Umpiring Bekons
 

I'll bite on this one as a few of the other threads have regressed into whose mother is worse...

If he is in the act of fielding a throw that would be fine. Otherwise you have obstruction which protects the runner as long as he does not violate FED or Club or League rules which at most levels require the runner to Avoid Contact. It's one of those judgement calls. Use the opportunities presented BEFORE that play to explain to the catcher that he shoud avoid blocking the plate without the ball.Jim Simms/NYC

Obstruction
 

It is obstruction according to FED 8-3-2. Also look at 8.3.2.G and 8.3.2.i. Someone told me to look at it this way. Is the catcher in the act of making a play while he is at home plate? In otherwords, is the ball coming towards him? If not than you call obstruction. Do not ask yourself if he can theoretically make a play but rather is he in the act of making a play? If the ball is coming towards him than he has the right to be there, if not it is obstruction. I hope this helps.

Greg.