Right-back: Max Aarons
Max Aarons was instrumental in Norwich's campaign last season that saw him make 45 appearances - the maximum he's ever made for the side in a single season.
Aaron has clearly honed his attacking instincts and improved on the quality of his passes. Making more than one key pass per game while averaging nearly 50 passes per game, the right-back has successfully complemented his defensive qualities with his efforts in the final third.
Nuno might still offer a chance at right-back to Matt Doherty, the Ireland international who played under the Spurs manager at Wolves last year. However, the 29-year-old didn't find consistent form during the year, and this will likely put him as second choice for right-back this time around.
Center-back: Cristian Romero
The 23-year-old had a scintillating last season with Atalanta, where he picked up six goal contributions as center-back Romero was also part of the Argentina squad that lifted the Copa America trophy. He played in the final, successfully keeping Brazil quiet throughout the game.
His work rate and current ability clearly has Spurs interested, especially because the club wants a center-back who can make an impact immediately. Aside from this, Romero is just 23, with the potential to become one of the best center-backs in the world.
The young center-back helped Atalanta finish in 3rd place, above Juventus, and Spurs will dramatically reduce their defensive woes if they can get him to play in England this season.
Center-back: Sven Botman
Lille conceded an amazing 23 goals throughout the course of the Ligue 1 last season. Losing only 3 games, they cantered to victory in the league, one point above PSG. Much of that defensive effort came from 21-year-old Dutchman Sven Botman making 37 league appearances for Lille.
It isn't surprising that Botman piqued Tottenham's interest. With Romero potentially lining up with Botman as half-back, Spurs will inject more pace and agility at the back.
Botman, like Romero, is young but capable of hitting the ground running. He's also going to be a potential long-term investment for Spurs, especially if his actions on the pitch can improve the club's standing this season.
Left-back: Sergio Reguilon
The Spaniard might have had an average - or below par - last season with the Spurs, but Nuno Espirito Santo will certainly have noticed Reguilon's performances in the Euros. The left-back flourished for his national side, setting up two goals in just three appearances.
Will Reguilon take that form into the new season with Tottenham? Or will he lose consistency and become a pain for the new management? Since there are no plans to purchase a left-back in this transfer window, it looks like Nuno is putting his faith in the 24-year-old.
Ryan Sessegnon, who is been on loan at Hoffenheim, will be a strong contender for the position. The 20-year-old was at his best last season, making 24 appearances and contributing 5 goals in the Bundesliga. It's uncertain if he will go on loan again this season, as Nuno might be counting on the youngster to break into the first team.