A World Cup winner with Argentina and one of the Premier League's most aggressive defenders, the Tottenham captain combines physicality, aerial dominance and composure in possession.
His style has often been compared to the traditional defenders Simeone has built his teams around throughout his managerial career.
Although Romero remains under contract, Tottenham now find themselves facing increasing uncertainty over their captain's future.
The North London club have already strengthened their defence this summer, bringing in Jan Paul van Hecke and Marcos Senesi, moves that many observers believe could prepare the squad for Romero's potential departure.
However, Spurs are understood to be reluctant to lose one of their most influential players without receiving a substantial transfer fee.
Reports indicate that player departures could free up both transfer funds and wage space, allowing the Spanish side to increase their offer for Romero.
This has strengthened optimism in Madrid that a deal can eventually be completed despite Tottenham's firm negotiating position.
His arrival would immediately improve the team's leadership, physicality and experience while providing Simeone with one of Europe's most accomplished centre-backs entering the prime years of his career.
For Tottenham, however, losing their captain would leave a significant void despite their recent defensive recruitment.
Replacing Romero's leadership and experience would be just as important as replacing his performances on the pitch.
Talks remain ongoing, and while confidence is growing that a deal can be found, several financial details still need to be resolved before Romero can complete the move.
Sevens Sports Arena Analysis
This transfer has developed into one of the biggest defensive stories of the summer.
