The 27-year-old only signed a new contract at Old Trafford back in September 2013, but injuries and a lack of form have resulted in speculation that he could depart the club during the summer.
Having recently been linked with a switch to Fiorentina, who signed Nani's United teammate Anderson on loan in January, his representative Andrea Pastorello has admitted that while a move to La Viola may be difficult, a transfer is still likely.
"Nani is a very important player and at this time the only thing I can say is that he is likely to leave Manchester. The problem for Fiorentina and the other Italian clubs is the player's salary. Surely we will evaluate all bids," he told ViolaNews.com.
"Our relationship with United is great. Fiorentina have to speak with Manchester United about Anderson and maybe it will be an opportunity to talk about Nani too."
Nani joined United in 2007 from Sporting Lisbon.