RB/Flex decision - Ty Montgomery, Joe Mixon, Isaiah Crowell, Golden Tate

PPR league. Decided to wait and see and sat Doug Martin last night, which looks like a mistake. Oh well. Now I have to fill one RB and one Flex with two of the following:

RB T. Montgomery (@DAL, might be questionable with rib injury)
RB J. Mixon (BUF)
RB I. Crowell (NYJ)
WR G. Tate (CAR)

I'm leaning Tate at the Flex since this is PPR and he has been the most consistent other than T. Montgomery.

If Montgomery was healthy then he is a no brainer, but I'm worried that rib injury is going to seriously limit him if he plays at all which has me considering Crowell or Mixon for my RB2 and both have been underwhelming.

I'm going with Jay Ajayi at RB1 even though he has sucked. Waiting for a big game.

David Johnson is stashed on my bench. I'm carrying 6 RBs - almost my whole bench.