The Mexico striker has been linked with a move away from Old Trafford this summer after struggling to hold down a regular first-team place in recent seasons.
But the 26-year-old could get an opportunity to shine in front of the Dutchman in LA, alongside Wayne Rooney in attack after the England forward pleaded with Van Gaal to let him start.
Speaking about Hernandez, Van Gaal said: "I will have to see how he plays.
"I have only seen him under another coach so far. He has arrived today and now I can see him play in a game. Then I can talk about him."
For the big stories and the banter follow us on Twitter: @tribalfootball