I would personally say no on this one! Although Welker isn't necessarily the top option in NE anymore I think he still has just as much upside and a much better QB than Fitz! Although if you can't start them both then it might be a good idea, as long as you are ok at WR and RB.
QB: Jake Locker, Ryan Fitzpatrick
RB: Jamaal Charles, Adrian Peterson, Trent Richardson, Peyton Hillis
WR: Dwayne Bowe, Vincent Jackson, Jordy Nelson, Marques Colston, Kendall Wright, Michael Floyd, Alshon Jeffery
TE: Vernon Davis, Heath Miller