Jose Mourinho has long been an admirer of the Brazilian left-back, who joined Juventus from his former club Porto in 2015, for a fee of 26million euros.
The United boss has been actively searching for a left back for some time, with Luke Shaw seemingly not being fancied by the Portuguese manager, and Daley Blind, Ashley Young, Matteo Darmian and Marcos Rojo all having played in the position.
Reports suggest Chelsea have pulled out of the race to sign him, leaving the door open for United to pounce for the attacking full-back, who has 10 caps for the Brazilian national team.
Antonio Conte’s men were strongly linked with a move during the summer, but failed to meet the demands of the Serie A giants, and instead opted to sign Davide Zappacosta from Torino, as he can operate on either flank.
Juventus have apparently changed their stance for January however, and are willing to allow Sandro to leave the club if their £53million valuation is met.