Make no mistake, Donovan McNabb is the Redskins starting quarterback. They aren't dumb enough to trot Rex Grossman out on the field against the Eagles, they know the city of Washington (and this website) would explode into a million frustrated pieces.
But making McNabb the starting quarterback for your fantasy team would be just as stupid as the Skins sitting him. He simply isn't fit to start in your league unless you play in a league that's deeper then 15 teams.
Even when Shanahan has trusted McNabb enough to put him on the field unimpeded, he hasn't been a very good fantasy football quarterback. He has made the Redskins a better team then they were last year, but he won't help your team to the playoffs.
But again, it all comes down to the other players on your roster. If you don't have anyone else on your roster capable of throwing a pass, then you should start McNabb. But if that is the case, then you clearly haven't been paying attention to your team all year and don't deserve to make the playoffs. Harsh, but true.
There are players who are probably still available on the waiver wire (Josh Freeman, Ryan Fitzpatrick, David Garrard) who I would feel better about playing then McNabb; who has to go up against an Eagles defense that just made Peyton Manning look like an actual factual human being.
McNabb will be on the field when the Skins host the Eagles, but he shouldn't be in your lineup if you want to win this week.