I've got a better idea. Do a sign & trade of BBD to get either Josh Smith or Marvin Williams from them. That'll give the Celtics a decent backup SF who isn't over the hill.
Except that I don't think ATL is in the hunt for BBD. Also it doesn't work financially for Josh Smith. Unless you meant Josh Childress.
And why on earth would you sign the one dimmensional undersized, overweight PF, in exchange for a taller, more athletic, defensive minded rim finisher. Makes no sense.