Probably AJ Pierzynski?
Who was traded to San Fran for Joe Nathan, Boof Bonser, and... (looking it up) Francisco Liriano, right! But more because we had this new kid (Joe Mauer) coming up in the catcher position, so playing time was gonna be scarce for one...
And yeah, i remember reading the same thing about him, that he kept watching Twins games while playing for the Giants, and was not quite the fierce competitor he'd been for the Twins...
He eventually got his World Series Ring with the White Sox... Not quite so quickly as Doug Mientkiewitz, who ended the Curse of the Bambino.