Who should I trade, Ryan or Vick?

[hoyaparanoia 0]

My current roster:

QB: Matt Ryan, Michael Vick

RB: Matt Forte, Ryan Matthews, Jacquizz Rodgers, LaMichael James

WR: Julio Jones, Percy Harvin, D. Heyward-Bey, Santana Moss, Greg Little, Kendall Wright

TE: Aaron Hernanadez, Kyle Rudolph

D: Denver

K: Prater

I want a strong RB to go with Forte and Matthews, especially early with Matthews recovering. It's a PPR league so I would love Doug Martin. I'm not sure if I would be able to get him for Vick straight up, but I might be able to for Ryan. I'm also going to release Moss and James for a backup D and backup QB after the deal, just waiting for my commish to upload the rosters... I can also try to get Sproles for Vick, but I really like Martin in a PPR... Let me know what you think...