The so-called "third party ownership" (TPO) is already banned in the English Premier League, but is common in some parts of Europe and in South America.
"The Executive Committee took a very important decision concerning the TPO, third party ownership of players' economic rights," Blatter said after a FIFA Executive Committee meeting.
"We took the firm decision that TPO should be banned. But it cannot be banned immediately, there will be a transitional period and a working group... Is working on that. It is very important."
Platini dubbed TPO a "danger", saying many players were no longer in control of their own sporting careers, often transferred each year to "generate revenue for anonymous individuals who just want to get their hands on some of the money in football".
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He said that if FIFA did not act, UEFA would take its own action.
"I want to take advantage of your presence here today to make a solemn request: please have the political courage to deal with this problem once and for all," Platini said to Blatter in that March meeting in Kazakhstan.