The Red Devils are whether to extend the 34-year-old's contract by another season.
Cavani has been tempted to move back to South America, and possibly join Boca Juniors, in the summer.
Asked about Cavani, former United loan star Ighalo told Sky Sports: "He is a good striker, he is doing well, there is no doubt about that. If an opportunity comes for him and he wants to go then that is fine.
"For me you people know this is a team I supported right from the start, you can't tell me twice about it, I am going to take the opportunity of staying but every man has his own decisions."