IDP Flex Decision

I have 2 flex spots in a tackle-heavy league:
1.5 Solo, 1.0 Asst, 3 Sack, 3 Int, 2 FF/FR

I have Jamie Collins slotted for one spot (at Buffalo, no brainer).  

My other choice is Nick Bellore or Jatavis Brown.  Brown is coming off his injury, so feels iffy to me still.  Bellore should theoretically be on the field all day, so that's the way I'm leaning.  Am I over-thinking this?

I lost JPP, so am rolling with Trent Murphy at DE.  L. Joseph at DT.  Wagner, Lee, and Posluzny at LB.  Collins and Bethea at DB.  

I would probably feel more comfortable with Bellore... Perryman has been playing pretty well too from what I can tell so I don't know if Brown will be taking such a large role off the bat. Good luck!