Tottenham manager Mauricio Pochettino’s new contract does not contain a clause allowing him to leave for Real Madrid.
The 46-year-old Argentine, who signed a five-year extension with the Premier League side last week, is the early favourite to replace Zinedine Zidane.
Zidane stepped down on Thursday after leading Real to a third consecutive Champions League title.
Pochettino is not believed to have agreed anything in writing or verbally with Spurs about joining Real.
He took over at Spurs in May 2014, and led to them fifth, third second and third in his four seasons in charge.
‘Pochettino would be Real’s first option’ – analysis
Andy West, Spanish football writer
A number of names are being circulated as potential replacements for Zidane, with the most heavily touted candidate being Pochettino.
It is believed the Tottenham boss would be president Florentino Perez’s first option. He has admired Pochettino since his time in La Liga in charge of Espanyol, a club with whom Real have friendly relations, and he was greatly impressed with the London side’s performances when they went head to head in the Champions League this season.
But Germany manager Joachim Low is also being linked with the job, despite recently signing a new four-year contract.
Soon-to-be-outgoing Chelsea coach Antonio Conte is another possible option, with Frenchman Arsene Wenger, recently out of a job at Arsenal, also being talked about as an outsider for the role.