"The important thing is, we should also protect the player," he told tell it like it is news.
"If the player wants to play somewhere else, then a solution should be found because if he stays in a club where he does not feel comfortable to play then it's not good for the player and for the club.
"I'm always in favour of protecting the player and if the player, he wants to leave, let him leave.
"I think in football there's too much modern slavery in transferring players or buying players here and there, and putting them somewhere.
"We are trying now to intervene in such cases. The reaction to the Bosman law is to make long-lasting contacts in order to keep the players and then if he wants to leave, then there is only one solution, he has to pay his contract."
Forget '39th game'
Meanwhile, Blatter has reiterated his stance over the Premier League's proposal to play a '39th game' overseas.
He said: "The 39th game as presented will never happen. To my knowledge what they (the Premier League) want to do is perhaps to play some of the League Cup matches somewhere outside of England. That's the last information I got.
"They should just forget about that."