And it has nothing to do with what "shape" he's in. We still don't know if he can block. We don't know if he's effective catching the ball out of the backfield. He is still struggling when to plant a foot and cut up on zone runs. He needs work on gets his shoulders lower and churning his feet.
Look, I think Green looked pretty good and showed a lot of promise, but as many FR need, he needs time to improve his game before becoming the starter. Right now Fitz is just better, plain and simple.
Now by mid-season, yeah, I'd probably look for Green to be #2 behind Fitz, and still a clear #2. I actually Smith between the tackles more than Green on short yardage situations, but don't run him outside, and I think Hayes should get some 3rd down plays (I think this is being saved for ND FWIW). Other than that, I'm not really impressed with the other backs as of now.