DA is on the budget restraint (probably orders from the owners). If the last year's salary ($84.3 millions) is the top line and Celtics already spent $74 millions already this year, that's only about 5 to 5.5 millions to spent on other players. Had Posey accepted the offer, Celtics would only sign minimum players for other positions. Anyway, it was pretty obvious to me from DA's Comcast interview.