It seems that Morris would be a great fit for this team. He's talented, on a great deal, and it doesn't seem like the Suns are asking for a lot. McDonough, the Suns GM has a good relationship with his former boss, Ainge. The Celtics also have plenty of draft picks of various worth available to deal.
Reasons why it may not have happened yet:
1) The Celtics don't want Markief's $24 million guaranteed on their cap the next three seasons.
2) The Suns don't want to deal another one of their talented players to the Celtics. McDonough (whose job is in danger) doesn't want to look like he got ripped off twice by his old boss Ainge.
3) The Celtics are really low-balling the Suns.
4) The Celtics are concerned Morris will be bad in the locker room and is not worth the risk (it seems like Isaiah would be able to provide a character reference here, along with Ryan McDonough giving Ainge the straight dope about Markief's character).
5) The Celtics really believe in their current big man rotation and don't have the minutes for Markief (hey, they're just possible theories, don't laugh).
6) The Celtics are saving their assets for a possible better deal at the trade deadline/in the near future.
7) The Celtics don't like Morris' game or don't think he's a fit.
What do you guys think?