Ehhh... teams dont ALWAYS offer fair market value for players. Teams probably see Law as a chance he will take a below market contract because he is injured. I would always offer a player like him a below market contract. You therefore leave room for negotiating and can get him below market value.
IE if a team thinks his market value is 3 million a year, they offer him 2 and negotiate up to 2.5.
I get what you are saying and agree, but its not always like that. There are always exceptions with injuries so I think teams are going to lowball Ty Law.