Arsenal boss Arsene Wenger has admitted he was stunned by reports that Fran Merida has agreed a pre-contract agreement with Atletico Madrid, but that the player may leave.
Wenger is powerless to stop the Spain Under-21 midfielder leaving in the summer, as his contract runs out, but they are still entitled to a transfer fee from his new club as he is under 23 years old.
"I fear the worst but I don't know," said Wenger. "We made him an offer but he could never finalise it for different reasons. He is at the stage where he wants to play and he needs to play. I don't know if he has signed somewhere else. I am a bit disappointed if he has."
Atletico Madrid president Enrique Cerezo has confirmed the club are interested in bringing Arsenal midfielder Merida back to Spain - but concedes they may have a fight on their hands to tempt the teenager to the Vicente Calderon.
Atletico have been closely linked with a move for Merida, whose contract with Arsenal expires this summer, and Cerezo admits the Rojiblancos are keen on signing the Barcelona-born 19-year-old for next season.
"Of course we are interested. He is one of the best young players in Europe,'' Cerezo told Marca. "But just as we are thinking of it, many other teams in Europe will be thinking the same. I'm sure that he has many offers because that is what someone of his quality deserves.''
Merida's representative, Joseba Diaz, insists nothing has been signed with Atletico or any other club, saying the only team they are currently in talks with are Arsenal.
"We haven't signed anything with Atletico because, simply, the only club with whom we are negotiating is Arsenal,'' he told Marca. "The absolute priority of the lad is to renew with them. I repeat: There has been no agreement with anybody.
"Only if we don't renew with Arsenal will it be the moment to talk with other clubs. There's been interest from four clubs in Spain but I've not sat down to negotiate with any of them. Arsenal have the priority. Moreover, as always, they are acting like gentlemen.''