IMO, these are the circumstances that will lead to us seeing Goff on the field:
1. Case gets injured when Goff is #2 (which could be a startling week to week decision from Fish)
2. Rams are down by 17+ points in a game when Goff is #2
3. Rams are 3+ games under .500; 1-4 or 2-5 or worse
4. At mid-season or later when their record is poor; and if Goff shows anything, in Fisher's mind it could help him get an extension
5. Stan dictates it
I don't see any other possibilities where Jared gets to play.