I wouldn't do that. Fitz has been great, yes, but I don't think he's a huge upgrade and Jennings is far and away your best and most consistent receiver.
I'm pretty good at WR with Marshall, Nate Washington, Santana Moss, and A.J. Green but shaky at QB (Ryan and I just picked up Cam Newton). Jennings is my most reliable WR, but I feel like I have enough flexibility at WR to sacrifice Jennings for a strong and consistent upgrade at QB.
