The notion that it would be a problem if Keenum played so well that it takes awhile for Goff to break into the starting lineup is simply wrong-minded.
And, as typical, the reason for the "problem" is because the Rams paid so much in draft stock to get Goff.

This is a false pressure coming from a schizophrenic mindset that somehow if you draft a QB high, and think he's going to be special, that he must become special immediately.

Pre-draft, there's few journalists or talking heads that don't council going slow with rookie QBs, and how much better it is for them to develop and carry a clip board for several games, or a full year, at least. But once the draft happens, all that goes down the drain and suddenly a highly picked QB must start immediately or it was a bad pick.

Anybody who has watched football for any length of time can see Goff's talent. But equally so it is clear that Keenum is way ahead of Goff right now. Of course. The guy has been in the league for 5 years, and has played in and started several games. He's now been in the same system with the Rams for the 2nd year, is more familiar with his WRs, and so on.

If I'm a betting man, I'm betting Keenum starts game 1, and then how and when Goff gets on the field depends on how Keenum plays and whether or not the Rams O is scoring the ball, and if they are winning games. Because Fisher isn't going to change QBs based on what happens during practice.

And in the longer run, this will be a good thing for Goff and for the Rams.