Costa has also been linked with a numer of other European clubs, including Manchester United, Real Madrid, Barcelona and Juventus.
“They have been watching Douglas since six months ago and they are convinced that he is the midfielder that they need. They have a strong interest in the player,” said the Brazilian’s agent, Cesar Bottega.
Brazilian side Gremio want at least £9.3million for the youngster.
Gremio vice-president Andre Krieger said: “If Villarreal intend to offer a bid of less than €10million, they shouldn’t even bother coming to Brazil.
“We have a price for the player and we are going to stand by it.”
Gremio president Duda Kroeff added: “Douglas belongs to Gremio and we are not going to sell him for a fee we don’t like. If a team is interested in him they will have to accept what we want.”
