The Lilywhites have been one of the more quiet sides around the upper end of the Premier League this summer, signing only Victor Wanyama and Vincent Janssen so far.
Silva emerged as one of the top wingers in the Primeira Liga last term, and earned a spot in Portugal’s EURO 2016-winning squad earlier this summer.
It’s understood that Spurs were monitoring the 23-year-old prior to the current window, and reports claim that they are now plotting a bid for him.
There is also interest from Zenit Saint-Petersburg and Porto, but Silva is believed to be more receptive to a Premier League switch.
The silky wide man was a part of Portugal’s European Championship win, albeit he only played one minute of game time in France.