The 23-year-old right-back has made 23 outings for the Portuguese outfit this season, assisting ten goals and netting two.
Porro’s impressive performances with Sporting Lisbon have sparked interest among several European sides.
Spurs boss Antonio Conte wants to recruit a right-back in the January transfer window and he has his eye on Porro.
Porro has a release clause of €45m and Sporting Lisbon have been clear it must be triggered for the player to go, a point reiterated by coach Ruben Amorim earlier this week.
However, it has been claimed that Tottenham are edging closer to reaching a deal with Sporting Lisbon to land Porro in the January transfer window.
Spurs are confident that they can reach an agreement in which they will pay the majority of the fee and the remainder through add-ons.
Emerson Royal, Japhet Tanganga and Bryan Gil, among several fringe players, have been offered by Tottenham to Sporting Lisbon as part of a possible swap deal.
The north London side have also floated removing their 50 per cent sell-on clause in Sporting Lisbon attacker Marcus Edwrds.
