The Feyenoord defender is highly rated by Dutch pundits, and has already featured seven times for the national side, despite being born in Portugal.
The 21-year-old has been watched by club scouts already, and a fee of £5.5m could be enough to tempt Martins to the Premier League.
The versatile defender can play either left or centre back, and would provide the competition Andre Villas-Boas is looking for on the left side, following Benoit Assou-Ekotto’s injury-hit season.
It is expected the north Londoners, who currently hold down third place in the Premier League, will allow loanee Danny Rose join Sunderland on a permanent deal to push this move through.
The Lilywhites’ are also tracking Eder from Sporting Braga, Sochaux’s Sebastien Corchia and Brazilian striker Leandro Damiao, as they look to bolster their squad in the summer.
Martins has made 56 league appearances for De Stadionclub, scoring three times.
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