Need help w/ Flex Poo Poo Platter

[LukeOutBelow]

10 team PPR, I have arguably the worst receiving corps in all of 2009 FF. Here's my rundown:

QB: Pey-Pey
RB: MJD
RB: Portis
WR: B. Marshall
WR: Steve Smith (NYG)
Flex: Need help choosing among...

Marshawn: will be lucky to split time 50/50 with F. Jackson
Kevin Walter: @OAK, 14th ranked pass D
Johnny Knox: vs. DET, 30th ranked pass D
Justin Gage: @JAX, dead last in pass D

Leaning toward Knox, but I can't tell if this is because I'm a Chicagoan. Thanks in advance for any thoughts.