Not really "the like", Mutu was an exceptional and singular case and he was sued for breach of contract for taking extra curricular drugs and making himself worthless. Remove the cocaine (and his un-saleability) from the case and there isn't a case.
The truth is, in Europe, a contract is more like a gentleman's agreement, purely because of how difficult it is to enforce as cases can take a very long time and cost too much money. However, neither party (and by that I mean club and agent) is stupid enough to break the status quo as if the players make themselves unsaleable by destroying the transfer market, then they'll destroy their own earning potential. A single test case could demolish the player/agent earning potential overnight.
If there wasn't the gross amount of money that there is in football I'm sure you'd see people walk all the time. Fact is, veteran players can actually buy out their contract if they have been with the club long enough anyway. None of them will ever do it though as everyone involved realises the effect it will have on all of their pockets.
