I wonder if the Cs feel Noel and Horford can play together. Offensively? NP. Defensively it's a little tricky, it seems. Noel would get dragged away from the basket defending PFs.
Better than our current situation. Right now Horford is getting dragged out to the perimeter guarding PFs, which takes him away from his best defensive strength of anchoring the defense and rim protection.
At least by adding Noel you'd always have a rim protector down low, no matter whether Al or Noel was chasing the PF.
Put it like this - replace Amir for Noel at the basket. Don't you think the much younger and more athletic Noel provides much more rim protection than the aged Amir?