Granted, that Romero hasn't been the same reliever that he's been in the past, but he did throw well in his 2/3 of an inning against Cincinnati and while Kyle Kendrick hasn't pitched since the regular season ended, he too could have been an option. Manuel could have started the inning with Lidge throwing in the pen and had an extremely short leash on whoever he sent out there, but it would have likely bought the Phillies one more inning before they would have had to start pushing panic buttons.
If you're not going to trust Romero and Kendrick to do their jobs, then why are they on the roster? Antonio Bastardo, who also hadn't pitched in the post-season, was left in to face Buster Posey in the seventh, giving up a double to the right-handed, hot hitting young catcher. Perhaps instead of going to Ryan Madson at that point, Kendrick could have come on to face Posey and given the Phillies a couple innings of work, saving Madson for later situations where he could have been more valuable.
There's no way to know how, or if, the outcome would have been any different had the bullpen been used differently. After all, Chad Durbin was used in his usual role and gave up two runs to let the Giants reclaim the lead after the Phillies had battled back. You never know how a bullpen is going to respond. One thing is sure though, Oswalt would have been better left to his starting role without an added relief appearance thrown in between starts, especially since he had already thrown his between starts bullpen session. There is now the risk that Oswalt has been thrown off of his routine for his Saturday start and with their backs against the wall, the Phillies need strong outings from their big three in the rotation.