With the start of the Football League season just three days away, Grayson has promised to make changes to his starting XI.
He said: "I'm disappointed with a few players' performances and we didn't perform as a team. We warned the players about what Preston would be like. They'd get in your faces, make it difficult for you, they'd leave their foot in, their elbows in, and they'll work you. We didn't handle it.
"It's frustrating for me, but it will be frustrating for the players when I pick the team on Friday and one or two are not in it.
"Everybody had an opportunity tonight to stake a place for Friday night and some of them have not taken those opportunities."
Huddersfield kick off the new Championship campaign with a trip to Cardiff City on Friday night.