Middleton is like Shulters and any others that came in late. They will be worked into the system bit by bit. Tebucky was a second teamer, now he is first team. Holliday mosied his way back into the starting rotation. Seau will be worked in just in time ( he will be the fourth LB in the 3-4, blitz package). Its just how Saban does things. He will slowly work you into the system and not put you first team just because people think that is where he will end up.
BTW, I thought Mckinney was better last night. I dont think Saban and Houck are going to give up on him yet, but if Middleton does enter the picture along with Ephraim, then Mckinney might see less playing time. But I do not think they will give up on him yet until he gets the full Houck treatment.