He's part of the mix but as was proven in the playoffs, he's a liability when it comes to rebounding. He'll be part of a center platoon but the key guy will be whoever they bring in to compliment him. Zeller can't be on the floor when you need stops late in games.
I had nightmares of Thompson beating him to every possible OR and wanted him traded on the spot and on the bench right away.
Then, Thompson abused The Bulls and Hawks in the very same way and I thought a bit better of Zeller. Afterwards, I checked his DREB% and his contested rebounds% - both are actually decent.
We should keep in mind this was his first year having a significant defensive role. Stevens joked it is the first time in his life being subbed in for defensive purposes. So yeah, he might get better defensively.