The Portuguese giants have reportedly enquired about the talented midfielder, who is valued at €12 million.
Sporting Lisbon midfielder Danijel Pranjic, however, says he is not aware of club’s interest in his compatriot.
“Nobody asked me anything about Mate (Kovacic),” Pranjic explained to Jutarnji List.
“Few weeks ago they enquired about that boy Halilovic (Alen, Dinamo Zagreb midfielder) and Hajduk’s Under-17 player (Josip) Basic, but there was no talk about Kovacic.”
Mateo Kovacic, 18, is widely regarded as one of the most talented midfielders in world football and he has seen his named linked with Europe’s top clubs.
Kovacic began his career at Dinamo Zagreb and already made 43 league appearances for the Croatian giants.
He has scored one goal in 20 Champions League fixtures and is currently a member of Croatia Under-21 side.