Re: playoff bench?
Larue will be on there to be the back up catcher and allow Javy to pinch hit. You wouldn't want to pinch hit Javy in the sixth and then have Ross get hurt and be left without a catcher for the rest of the game. Also, although I don't care for Clayton he has come up big recently and will be on the roster over Castro for sure.
It will be:
6) Extra pitcher or Castro??
There really isn't much in the minors that would suffice for a pinch hitter on a playoff team so I think this will be it. Its not great but not as bad as some make it out to be. It helps that the starting 8 is very solid top to bottom.