A number of recent reports in Italy have suggested Milan have earmarked the Netherlands international as an addition to their attack and are preparing a €10 million offer.
Galliani has admitted that the 20-year-old is on their radar but insists they will not be buying another wide player until they have sent someone in the opposite direction.
"El Ghazi is a player we like," Galliani told reporters. "But we cannot do anything unless one of our other wingers leave the club first.
"That's the way things are at the moment."
El Ghazi joined Ajax from Sparta in 2013 and has developed into a key player in Amsterdam, scoring eight goals in 13 league appearances this season.