Should be for 50% of George's salary 7.9 million.
It must be used on a player in the final year of their contract.
The incoming player can only make the amount of the exception + $100,000. So 8 million. This means Green, Wallace and Thornton are all out as far as options.
I don't see the Celtics being in a position to help/benefit from the Pacers as Bass is really the only player in the last year of his deal making around 50% of George's salary and the Pacers have West and Scola at PF.