They should've started him last week for his 1st start instead of this one vs a top team.
IMO, if they wanted to start him in the first half of the season, the best game for it would have been the November 3rd game (Titans). It would have been game 9 (a/k/a the new mid-season), and it would have been against the Titans.
But that's just from a guy who doesn't know the specifics of that actual plan (me), and might have been being extra cautious. You're spot on about not starting him this week, though, IMO.