Abu Aardvark notes a controversy about sports free agency and sharia law with some amusement. I'm not as amused (well, ok, I am) because there's a strong overlap between Sharia and Talmudic law in the area of contracts and moral business behavior. As far as I know, no Rabbi has ruled on the free agency issue, but there's plenty of Talmudic and Sharia material on indentured servants, slaves, artisans and contracts which would be entirely relevant to the question.
Just a reminder that there are other ways to view business behavior in free markets than simple "market order" (i.e. reacting to purely fiscal measures of behavior).