What happens in this scenario?

watching the Braves game this afternoon... play at the plate and the ball is knocked loose from McCann and rolls a short distance away. In the meantime the Padres 3B coach has come more than 3/4 the way down the line with the runner. Seeing the ball knocked loose the Padres' runners advance. McCann picks up the loose ball and prepares to fire to third but the 3b coach is in the way. He ducks and McCann makes no throw as there is no chance to catch the runner advancing. But... what would have happened had he let loose a throw and nailed the Padres 3B coach in the back that far down the line?

 

interference, plain and simple

 

Yep, I agree. It doesn't matter if the coach was in the box--it's not a free safety zone. If he interferes with the play, it's interference.

 

so runner at third out? Is there a judgement aspect to this? In other words, had McCann thrown the ball and hit the coach in the back here is the runner automatically out even tho there apparently was not a chance of throwing the runner out?

 

Let me be more specific. It is a judgement call. The umpire must decide whether the interference was intentional or not. An umpire may correct me, but a coach is supposed to remain in the box unless he is getting out of the way of a player trying to make a play.

In the scenario you mentioned if McCann made the throw and it was interfered by a coach, the umpire would be right to rule interference.

But interference is not always called. To give an example the rule is specific if a coach makes any contact with his runner, the player is ruled out..and in some cases it has happened where a coach aided a fallen runner rounding 3rd. However, it is not always called.

Remember when McGwire hit his 62nd HR and was chest bumped by 1st base coach and nearly missed 1st base...actually he should have been called out.