Well, I said solid season. That would mean as a 30 going on 31 year old QB in 2019 he's got a few solid seasons under his belt -- NONE elite. And a history of knee injuries. I wouldn't have a problem "dumping" that at 31 years old for unproven but potential to be great.I have a problem with this way of thinking. In your scenario, we have RT that has a very solid season and we are going to dump him for a player with unproven abilities? That makes little sense.
Instead, if we get a developmental QB that progresses well and RT has a mediocre (or worse) season, we are then more comfortable moving on and see what we have in the youngster.