In the quest for the NL Wild Card (or even NL East), there's a little known secret about the Phillies - they can't beat good teams. If that doesn't change, you can forget about them.
All the teams up for one of the two disputed NL playoff spots have had some success against winning teams, except for the Phils. They have dominated teams under .500 but struggled mightily against teams over.
Your sister site on SB Nation, The Good Phight, begrudgingly explains the situation here.