This Italian website is reporting that the Celtics may be hiring David Blatt (wikipedia bio) as an assistant coach. No confirmation from US based media that I can find as of yet. - hat tip to Roy Hobbs for finding this
Update: Apparently Jonathan Givony made a phone call and has confirmed that there is no truth to this rumor. Which would make sense considering that the team stated at the end of the year that they had no intention of adding to the coaching staff.