Catcher obstruction... Men's ASA SP
 

A little confused about the obstruction rule. Lets say a runner rounds third and is heading home, there's going to be a play at the plate. The catcher is standing in the base path and we have a collision before the ball reaches the catcher. By the rules this is obstruction, but isn't it also the runners responsibility to avoid contact?

Yes, but no penalty unless flagrant.

Lets say the catcher catches the ball while in the base path and tags the runner and we have a collision. Is the runner safe because of the collision?

I'm confused as to the sequence... did the catcher catch the ball before or after the collision?

Welocme a(board), Agreen. Hope we can help you.
We have frequent topics about OBS, but I'm not sure which to recommend as they usually include too many what-ifs and wrong answers.

A collision is not always OBS. It is OBS only if the fielder hindered (impeded or altered) the runner's approach to the base without possession and control of the ball.
In the example, even if in the base path, the runner might not have been hindered, so the collision does not prove anything. If the runner was hindered before the fielder had the ball, then it could be OBS; but again the collision itself doesn't prove it.

The umpire has to be watching the play and the players positions and reactions and timing; then put that all together like any judgement call.

I read it as sequenced as in the sentence: catch - tag - collision, but catch-collsision-tag still has catch first.

Let me rephrase: The catcher catches the ball while standing in the base bath, makes the tag basically at the same time as the collision.

A fielder in possession of the ball cannot commit obstruction. However, the runner MIGHT have been obstructed before the catcher gained possession - e.g. the runner deviated before the ball arrives, then the ball arrives, then the collision, then the tag. The obstruction (runner deviated due the the catcher being in the way) occurred before the catcher had the ball.

OTOH, if the runner continued running with no deviation or other indication he was impeded (in your judgment), and the catcher catches the ball, then the collision, then the tag, the runner is out.

Also, in this last scenario, if you judge the situation to be "a defensive player has the ball and the runner remains upright and crashes into the defensive player" (ASA 8-7-Q), the ball is dead and the runner is out for interference. However, do note that not all collisions are crashes.