The 20-year-old penned a new deal at the club until 2017 on Thursday, with the option of a further year on Thursday.
"Yes, it is the strategy of the club. When I came here there they told me that they wanted to have more youth academy players in the first team," said Van Gaal.
"Also the rule in the Premier League that you must have a certain amount of players in your own squad is also important.
"I am happy that we can sign players from our youth academy and our players are very popular as we also have a lot of youngsters out on loan and we can pick and select the clubs where the players can play every week, that we have seen also with Reece James, Michael or Will Keane - that is also a strategy.
"I believe in players that you have educated in your own youth academy, maybe that is the reason I am sat here."