Again, two games at the start of the season after a WC when Dybala wasn't 100% fit (Allegri even said it out loud, and we saw it in the first game).
So, Douglas Costa not starting is fine but Dybala not starting in two games means a lot more and sets off alarms because he isn't as good or lauded as much by the coach (acc to you). That doesn't make much sense.
It'll be interesting to see if Allegri plays him as a F9 like he should or plays a 4231 more often, but until more games are played, we don't have much data or sample size to react on.
First six months of last season when Dybala was in form.