Should I drop Willie Parker for David Garrard?

If he's really the only option you have to drop, then yes, don't hesitate. Pick up Garrard. He's actually a great play this week. He had a great game against TEN earlier this season. He will help you win much more than Parker right now. Plus if Garrard has another nice game this week, he won't be available in your league much longer. Keep an eye on Parker though. While he may stay a FA for a bit, once he gets healthy he could be a factor come seasons end.