Joel Sherman:

After the 2007 season, Rodriguez has the right to void the final three years on his contract and declare free agency. He would be walking away from $81 million (of which the Yanks are responsible for $51 million, with the Rangers picking up the rest). ...

Following the 2007 season, Rodriguez will gain leverage to potentially follow one of three paths: 1) to opt out as a free agent; 2) to push the Yanks to extend his contract upon threat of opting out; 3) to use the threat of opting out and the Yanks getting nothing to push the Yanks to trade him to a desired spot so that he does not have to forfeit the $27 million annually.

Boy, that contract was a monster.