The Chilean midfielder is seemingly close to moving to Italy after his agent claimed that he is optimistic about the state of negotiations with the Serie A outfit
The Chile international's future at the Estadio de Alvalade has been put into doubt after he did not take part in the Pepe Super Cup triangular tournament with Atletico CP and Belenenses on Wednesday and missed Thursday's training session.
Portuguese sources claim Fernandez will cost Fiorentina a fee in the region of €4 million, with the player's agent Alejandro Santiesteban now hinting that talks are at an advanced stage.
"It is true that we are working on a transfer to Fiorentina, things are going well," Santiesteban told Maisfutebol.
"But you know what football is like. We will not say it is done because it is not, there are still details to address.
"Everything should be clear in the next few hours."
The former Villarreal playmaker, who signed for Sporting in 2009 in a €3.6m deal, has only one year left on his contract with the Portuguese capital club.
He has scored 19 goals in 115 competitive appearances for the side, playing a leading role in the team despite being frequently plagued by injuries.