a couple of other points - another factor which also has to be considered in this QB equation is Bridgewater's medical condition(the Vikes did not think((as Zimmer said)) he could withstand the rigors) and McCowen who for the most part(particularly whenever he has played significantly) has almost always ended up injured
another point, playing Washington next week is off a short week, on national TV, and on the road - if the team wants to nurture Darnold(maybe they do not) - it doesn't seem like they'd foist him into a starting situation there. However, as stated if he were to do well again off the bench - he'd seemingly would have to start against the Giants to be the starter against Detroit opening night. This leads me to the final preseason which is on the road(like opening night) and in a nasty place(albeit preseason), and it would seem Darnold would might be best served to get a taste & experience of starting an NFL game on the road - off a somewhat quick turn around game against the Giants.
in any event - as Parcells used to say -"we'll see"