Re: Aroldis pitching in a 6-0 game? What was Dusty thinking?
I know this won't satisfy the OP, but the explanation is quite simple, and most managers would do it (following some of the unwritten rules of baseball).
1) You don't use your "closer" in a non-save situation.
2) You do use your next-best bullpen arm, especially if he might be a future closer and he can "audition" in a "fake save" last-inning situation.
Not saying I would necessarily follow those rules (I don't like the whole "closer" concept), but I know Dusty loves those kinds of "rules" (the catcher hits 8th), so there ya go.