I agree with your 13 mill figure.
However, remember that because of the failures of Minaya, his succesor will probably have a different approach to re-stocking a team whose pitching is clearly flawed.
Besides, the Sox have more money coming off the books, much more flexibility to accomodate V-Mart, a better stadium, and this is a place he likes. Seems like a win-win situation for the Sox if they intend to bring him back.