With Horford back, the center position is crowded. You have Williams, thought to be the future and a super athlete but often injured. Tristan Thompson, a tough rebounder but doesn’t have the ability to stretch the center. Tacko Fall, an interesting projects but how long do you wait to decide if there is a long term investment? Luke Kornet is the odd man out and Fall may be not be around next year as well if Celtics view Brown as a potential future center to compliment the rest of the team. Horford is a short term similar to Thompson. Look for more dealing.