For some reason the Mets do not play well in Pittsburgh. Below I pulled out the Mets numbers when the play Pittsburgh in Pittsburgh all the way back to 2004, when David Wright joined the team. Over that time, the Mets went from horrible, to awesome, to horrible. The Pirates over that time have just been horrible.
2012: 0-1 @ Pitsburgh
2011: 2-2 @ Pittsburgh
2010: 2-1 @ Pittsburgh
2009: 0-3 @ Pittsburgh
2008: 3-1 @ Pittsburgh
2007: 2-1 @ Pittsburgh
2006: 0-3 @ Pittsburgh
2005: 1-2 @ Pittsburgh
2004: 1-2 @ Pittsburgh
Total: 11-15
I know its only 4 games below .500, but you are talking about the Pirates of the last decade. A winning team should be over .500 against the Pirates, and at least 4 games over.
Just numbers for thoughts.