United have been heavily linked with a move for Real Madrid’s Argentina international, as well as Fiorentina’s Colombian wide man Juan Cuadrado.
And Van Gaal has indicated it is this position that he will look to address before the transfer window closes, suggesting that his current squad is not very well balanced.
Vice-chairman Ed Woodward has insisted this summer that United are prepared to spend heavily and even break the world record, but Van Gaal feels it is most important to bring in the right players.
Asked about Woodward’s comments, he said in the Sunday Mirror: "It is a strategy of Manchester United to do that. At this moment, we have five No.9s and four No.10s – and we don’t have wingers to give us attacking width.
"Or, I should say, we don't have wingers of the highest level, like Ronaldo or Di Maria or somebody like that. So, I have to play in another way – and you have seen that already. I only buy when I think we need to buy – in the position that is necessary."
Van Gaal left his role as Netherlands manager to come to Old Trafford and a number of the players he took to the World Cup are reported to be possible targets, including Ajax's Daley Blind.
He said: "If they are at the level I want them to be, then I will sign Dutch players. Nationality isn't something that concerns me.
"But Dutch players are usually cheaper than players of other nationalities and they have usually been very well educated in the Netherlands, I believe.
"But they have to be of a level than can play well in the English Premier League. You have to ask if that is the case with every player."