Sandro has forged a reputation as one of the best attack-minded full-backs plying their trade in Europe since heading to Turin in 2015.
And the 27-year-old has attracted plenty of admiring glances from managers across the continent, including that of Jose Mourinho.
The Manchester United boss is in the market for reinforcements this summer as he seeks to build a side capable of challenging champions Manchester City.
And signing a long-term replacement for Luke Shaw and stand-in left-back Ashley Young is one of his top priorities.