"I am not at all opposed to the idea," Platini told a news conference after a meeting with Serbian Football Federation (FSS) chief Tomislav Karadzic and government officials.
"But not being opposed to something doesn't mean I am automatically for it. At the moment, the UEFA statute does not allow such an option.
"It requires a joint soccer and political project by several countries in the region and their unified ambition to compete in a single league.
"If there are enough interested parties and the project turns out to be feasible, the UEFA executive committee would be prepared to look at it and make a decision.
"It is an interesting initiative and such a league would give teams from this part of Europe a chance to compete on a higher level with their wealthier Western rivals."
Officials from the former Yugoslav republics, mainly Serbia and Croatia, have launched sporadic bids over the past few years to form a joint league with the aim of improving the poor quality of football in the region.
But the idea also has its opponents, who argue that matches between teams which once competed in a single league in the former Yugoslavia would rekindle ethnic tensions that tore the country apart in a series of bloody conflicts.
Football encounters in the Balkans, especially local derbies, have a history of crowd trouble and Platini told the FSS that eradicating violence was a basic condition to move forward.
"UEFA has zero tolerance for violence and racism and we all know that Serbian fans have not behaved as well as we would have liked them to in the past few years," he said.
The Serbian FA paid a heavy fine after their fans racially abused England's black players at the Under-21 European Championship in the Netherlands in 2007.
The same year, Serbian champions Partizan Belgrade were kicked out of the UEFA Cup after their fans started a riot at Bosnian rivals Zrinjski Mostar.
