Japan Football Association (JFA) President Junji Ogura expected a decision to be made by FIFA after emergency talks in South America, local media reported on Saturday.
Ogura met his Argentine counterpart Julio Grondona earlier this week and was persuaded to rethink Japan's pullout as guests at the July 1-24 tournament in Argentina.
"Grondona knows (under FIFA rules) European clubs do not have to release their players for the Copa," Ogura told Japanese reporters. "He called (FIFA President Sepp) Blatter and Blatter has said he would consider changing the rules.
"Grondona knows that there are many Japanese players who play in Europe and told me CONMEBOL would take responsibility and negotiate their release."
There are currently 28 Japanese players at European clubs and Ogura is also set to make a fresh plea with J-League sides to cooperate.
A 9.0-magnitude earthquake and massive tsunami on March 11 killed more than 12,000 and has left over 15,000 still missing and thousands more homeless in north-east Japan.
The J-League, as with most of the country's professional sports, has been thrown into chaos.
"I was very moved (by Grondona's offer)," Ogura told the Nikkan Sports newspaper. "I would like to sit down and talk to the J-League about it."
Japan, who played as guests at the 1999 Copa America in Paraguay, were drawn with hosts Argentina, Bolivia and Colombia.
