With the Portugal international out of favour at Old Trafford and struggling for game time, a loan switch has been mooted.
Nani has long been linked with a switch to Serie A, with top Italian clubs having been trailing him for some time.
It could, however, be that he is soon heading back to his roots.
A product of Sporting's academy system, Nani is still held in high regard in the Portuguese capital.
A spell back at the club that helped to launch his career before selling to United in 2007 could offer Nani the regular opportunities he needs ahead of the World Cup, and president Bruno de Carvalho has opened the door for homecoming.
He told the Portuguese press: "I am surprised because officially we have made no approach.
"Nani is one of ours and he will always be well received here. If there is any chance of doing something then we would be happy."