The 17-year-old is yet to make the breakthrough into the Sporting senior setup, but he has impressed for the Under-23 team.
Fernandes has scored five goals and created two more in 28 appearances at that level this season, drawing the attention of a number of Europe's top clubs.
However, Portuguese outlet O Jogo reports that Arsenal have sent a representative out to Portugal to open talks with Sporting, who remain desperate to keep him.
Fernandes currently has a £40m release clause in his contract at Sporting, but the Lisbon outfit are keen to tie him down to a new deal that would see that rise to £90m.
The youngster's representatives are cautious about placing such a hefty fee on his shoulders at such a young age, though, and want any increase in his release clause to be capped at £70m. body check tags ::