Need RB for my flex spot

HPPR. I am starting Kamara and Barkley. I have Murray who did well while Kamara was out and thought he may have earned more touches, and I have Singletary. (Also have Ballage but that’s a definite no). Which do I flex?

I would start Singletary for sure. He showed last week what he can do with a decent work load, the Bills would be crazy to keep feeding Gore, plus Singletary has great pass catching ability.