The 24-year-old is expected to be one of the most in-demand players during the summer transfer window following his excellent performances for the Portuguese club this season.
Fernandes, who scored 32 goals and registered 18 assists, has already been heavily linked with Manchester United, Manchester City, Tottenham and Inter.
But according to Correio da Manha, Liverpool are the first club to make a formal bid as they have submitted a €45m (£40m) offer.
Sporting, however, are hoping to receive a significantly higher fee for the Portugal international, given the number of teams who have expressed an interest.