1) I don't see a rookie starting this year.
2) I see a trade coming down at some point to address the lack of starting big men.
Anyhow, I think it is Brown who finds a way to earn a staring spot that allows the Celtics to move AB or Crowder to fix the PF/C issue. (if no Hayward. If Hayward, he could still earn that spot turning either AB or Crowder as the 6th man type)