The news will increase speculation about the future of Toffees full-back and star performer this season, Leighton Baines, who is being linked with a transfer away from Goodison Park in the summer.
Despite having Bryan Oviedo on the books, Everton boss David Moyes appears keen to boost his defensive options and has sent scouts to watch Marcal feature for Portuguese club Nacional.
Nacional, who are currently 14th in Portugal’s top division, are yet to receive any offers for the 23-year-old but his agent Lee Payne has confirmed the Toffees have registered an early interest in the player.
However, he warned Everton are one of several clubs to have watched the defender in action and they are likely to face stiff competition for his signature.
“We know Everton have watched him, that is true,” Payne told Sky Sports. “But Fernando has been playing very well and a number of clubs are following his progress.
“As far as we are aware no bids have been made but we know a number of clubs have him on their list and it would not be a shock if someone did push ahead with something this month.
“But Fernando is happy and settled and so if he does not move in January that is no issue at all.”
The Sao Paolo born Marcal has made 26 appearances for Nacional since joining last January. His current deal runs until summer 2015.