The young Brazilian is being linked with a January move to Europe.
"We received two proposals for Mario Fernandes. "Specifically, they are from Real Madrid and CSKA Moscow, although both have been rejected, because we are not satisfied with the amount offered," said executive director Pablo Pelaipe.
"We believe that the player will remain here at least another year. He has to be with the team. If someone wants to buy Mario Fernandes, his market value is $25 million (€19M)."