Either Bender or one of the point guards.
Chandler is, strangely in my opinion, rather down trodden on this board. I think he'll be adequate as a back up center.
Chriss will either find his own or limp around as a low rate reserve for several more years.
Bender though... IMO this is his make or break season. He's a 3rd year pro, as much as Chriss gets ripped he isn't airballing 4 foot shots. Bender has multiple plays that were flat out embarrassing in the Summer League. As an offensive player he wobbles between inconsistent and disaster and while I've watched him play good defense, the numbers are hard to argue against; overall he has been a terrible defender. I'm rooting for him but he's a boom or bust player right now and IMO his boom odds are not high.
And... between Knight, Okobo and Harrison... no one stands out, the entire group might be a disaster. I like Okobo, but I don't think he's ready yet, I'm not sure Harrison is an NBA player and... until proven otherwise... Brandon Knight is Brandon Knight... which should make him the default pick for worst player.
Anyway... I think it's between Knight and Bender. I don't think Chandler will be in the running at all.