Do you have any 2013 statistics on pitching during the 7th to 9th innings (Pirates compared to the rest of MLB)?
It seems to me that the Pirates must be at or close to the top in categories such as runs-allowed, ERA, strikeouts, etc. for those innings. Their bullpen has been amazingly consistent. Of course, Melancon and Grilli have been practically unhittable, but in addition Watson, Wilson, Mazzaro, and Morris have also done very well.