Pep Guardiola is expected to bring in a full-back in the summer as part of his plans to strengthen his squad.
He allowed Joao Cancelo to leave on loan in the winter window and is tipped not to count on him next term even if he returns from Bayern Munich.
Manchester City’s recruitment team are scouring the market for full-back options ahead of the end of the season.
And it has been claimed scouts from Manchester City are keeping a close eye on Porto’s 23-year-old right-back Mario.
A product of the Porto academy, the defender has progressed through the ranks with the Portuguese giants and is now a key member of the squad.
He has already made 93 appearances for Porto and is now being watched by the reigning Premier League champions.
But Mario has other European clubs following him as well with Inter and Real Madrid also looking at him.
It remains to be seen whether the scouting leads to Porto receiving a big offer for him in the summer.
