I find the situation puzzling. Bigsby isn't special and he's obviously not trusted on passing downs.
Honestly think they still want ETN to be the guy......he just isn't playing well right now.
You don't really have to be special to be an effective RB, and Bigsby's rushing metrics have been as good as anyone in the league this year. Besides, I don't think anyone can realistically say Etienne is special either.
I'm not sure why Bigsby isn't being used in passing downs - maybe they don't trust him protecting Trevor just yet.