Mixon, Abdulla, Rishard matthews?

Need help choosing my RB2 and Flex. PPR
Im leaning more towards abdullah and Mixon as my flex. I also have Rishard Mathews, crabtree, cohen, bryant, and ty momtgomery in my bench

I’d flex crabtree or Matthews over Mixon ATM. Although he is getting the touches he isn’t doing anything with them ATM.