Here's what the website says now:
In the event that a game is not necessary and therefore not played, all single game purchases for that game will automatically be refunded to the card on which it was purchased. No refunds will be issued for played games for any reason.
Any single game tickets purchased through Tickets.com, over the phone or online, for games that go un-played will have the face value of the ticket and the convenience fee refunded. All other fees are non-refundable.
Season Ticket Holders – Postseason strip payments for un-played games will be applied toward your 2013 season ticket plan. The handling fee is non-refundable. Any single game tickets purchased through a Season Ticket Holder presale will be automatically refunded to the card on which they were purchased.
Refunds for un-played 2012 Washington Nationals postseason games will begin to be issued on Monday, October 22. Please note that refunds may take 7-10 days to process.