The 20-year-old Colombia international midfielder is reportedly being monitored by a host of top European clubs, with Sebastiani revealing that the Primeira Liga champions are closing in on completing a deal. 

He told Radio Mana Sport: "Quintero appeals to many clubs, but in pole at the moment are Porto."

Quintero has been recognised as one of the most promising prospects from South America and Sebastiani added: "The Colombian will cost no less than €10 million."