Mourinho faces a crisis in the right-back position and is understood to be on the hunt for a player he can rely on.
The Spurs boss doesn't appear to rate Kyle Walker-Peters and is not sold on Serge Aurier either.
Cancelo only joined City last summer in a £58m move from Serie A champions Juventus.
But the Portuguese international has only featured eight times in the Premier League this season and is believed to be growing impatient.
It's reported that Cancelo's main concern is that his place in Portugal's Euro 2020 squad may be under threat.
However, Spurs aren't the only ones offering the 25-year-old a way out as Barcelona have also registered an interest.
Barcelona's new boss Quique Setien is thought to be on the look-out for a right-sided player.
It's believed Spurs are the closer of the two sides to agreeing a deal, believed to be in the region of £52m.
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