From the Herald:
Allen, tired of being offered as trade bait by Danny Ainge in each of the last two years, was also being offered trade security by the Celtics, either in the form of a trade kicker or a no trade clause.
But according to a league source, Allen’s request from the Celtics went beyond the pale - reportedly a demand for a three-year, $27 million contract. The Celtics, according to the source, were in the process of attempting to talk Allen down from $9 million to $6 million per year.