The van Gaal era is in full flow now, with the former Netherlands boss replacing David Moyes at Old Trafford. Transfer activity is expected to increase now, despite having already signed Southampton left back Shaw and Atletic Bilbao midfield Ander Herrera.
For now, the attention is on pre-season football, where van Gaal is testing the 3-4-1-2 system that he used at the World Cup this summer with the Netherlands. It's so far, so good as United have won every pre-season game - but the aforementioned Shaw is already in trouble.
The £27m signing is tipped to be England's left back star of the future, and United even let long-serving Patrice Evra leave the club for Juventus in order to truly hand the baton to Shaw. Yet manager van Gaal was critical of the 19-year-old, saying that he isn't fit enough to play yet - and Shaw agrees.
"To play in this formation you have to be really fit. I am fit but I am not at the high level he demands," he said. "I have got to get fitter to get up and down. It's something I have got to work on. I didn't come into United thinking it would be much harder. That's something I think I made a mistake on."
Shaw did play 45 minutes on Tuesday night as United drew 0-0 with Inter Milan before winning on penalties, and Shaw felt that his fitness had improved in that game as he embarks on a personal training plan in order to get himself up to van Gaal's high standards.
"I felt great. I could have played another 45 so that's something that shows there is a progression there after the last game," Shaw added. "The focus is now to get fitter and fitter and be flying by the start of the season."