Yesterday is a great case in point.. late in a very close game (Game 2) Rocco pulled Farmer and pinch hit Castro. It didn't succeed as Castro was out but it was the correct move by Rocco.
Did it affect the outcome? Maybe. Maybe Castro made a play Farmer wouldn't have. They won in any event.
All Rocco can do is put the best players in the position to succeed most often, pitching, hitting, defense.
The majority of the end result is on the players.