Mauricio Pochettino is yet to enter the transfer market this summer, and the loss of Kyle Walker to Manchester City has left a hole at the back for the Premier League runners-up, particularly with Kieran Trippier suffering an ankle injury during pre-season.
Goal understands that Cancelo, 23, has been earmarked as the man to replace the England international, though they will have to fight off interest from the Bianconeri.
Juve are also in the market for a right-back having lost Dani Alves to Paris Saint-Germain, and have been linked to a cash plus player deal with Los Che that could possibly include Tomas Rincon.
Spurs, meanwhile, would have to meet Valencia's asking price of £25 million, a fee that should not stretch the bank balance in north London too far after the record £50m windfall they received for Walker.
Cancelo had also attracted interest from Chelsea, but that is now waning, leaving Tottenham as his most likely destination in the Premier League.
While Pochettino has not mentioned any specific names in his statements to the press in recent days, the Argentine did allude to his club's need to reinforce before the transfer window slams shut.
"For sure we're going to spend," the manager had signalled to talkSPORT on Wednesday.
"We're going to strengthen our squad and sign some players who can help us fight. We need new energy in the team.
"We have a very confident team who are ready to challenge again for a big season, but it's true we have the responsibility to try to provide some new energy every season.
"I'm sure that will happen and we'll add some players before the end of the transfer window. We are working hard to deliver that and ensure that by the end we add a few players, maybe three or four. We'll see. We are so close to making it happen.
"The transfer market is a little bit more relaxed now. The other big sides have spent almost all their money and now it's our moment. It's Tottenham's time to get involved."
Cancelo started his career in the Benfica youth ranks and first moved to Valencia at the age of 20, Los Che deciding to make his loan move permanent the following year after a promising debut season in La Liga.
He has gone on to become a key part of the Valencia side, missing just three Liga games last term in what was a roller-coaster campaign for the club.