From Shams at the Athletic:
The Celtics offered Brown, guard Derrick White and a draft pick to the Nets for Durant, sources said. The proposal was rejected, and Brooklyn has asked Boston — in any proposal — to include Brown, Defensive Player of the Year Marcus Smart, draft picks and potentially one more rotation player, those sources added. Currently, the Celtics are less inclined to include Smart along with multiple other player assets or pick assets, but the franchise is mulling over next steps on how to approach discussions.