If this were 2011 when Enes Kanter, Jan Vessely, and Jonas Valanciunas all got drafted in the top 10 I could totally buy that Zizic might be a lottery pick. The thing is The Jazz, Wizards, and Raptors all DEEPLY regret those picks. Those guys are all bums who don't matter in the NBA - which is unfortunate since they're the players who Zizic most resembles.
Vassely, certainly. Kanter and JV are capable bigs off the bench though. If you can manage to temper expectations for Zizic, he should deliver well for a late first rounder if his comparable is Kanter or JV.
For instance, Kanter is a stark minus at defense, but his pick and roll game with Westbrook can be very effective - imagine the same with IT4/Fultz. If Zizic can manage to be a better defender than Kanter (a not so tall task that I think he is more than capable of fulfilling), he should certainly find his way into the rotation.