They were only down 4-0 when Rusin took over. Considering that they had averaged 10 runs a game over the recent homestand, I think it's reasonable to have assumed the game wasn't entirely out of reach at that point. I do agree that they might as well have gotten another inning out of Senzatela and then read the tea leaves after five innings rather than making the move after four, but at this point when they bring Lyles into the game it's essentially a surrender, and I can see how Bud may not have viewed this game as that sort of situation at the time.