a pinch-runner / defender like Robles is probably more valuable in the post-season than the 8th guy in the bullpen. You could get the 18 inning game again, but you have extra off days and the like so I don't see that 8th arm being used often. A PR is closer to an end of game reliever in terms of when you'd use him (close / late) except you'd be short on runs rather than ahead.
You're not gonna have a game go 18 if you let Blanton pitch.
