Few problems with that. You should still want to get equal value in a trade, even if you're using monetary savings afterwards. Melky + 9.5 mil was still likely not equal value for Cameron. Second players like Dunn, Abreu or Perez will have to agree to sign here. You can try to sign one of them, but it's no guarantee. Third, your example of the complete deal isn't totally complete. The complete deal would be Cabrera and Dunn/Abreu/Perez for Cameron plus the rest of the free agent's salary. Dunn is going to cost more than ten million, so you need to factor in the remainder of his contract as well.