The Netherlands boss has had to change his plans following an injury to his "head of incidental pressing" — a player that his new club does not currently possess.
It threatens to make him the must-have accessory for every ambitious side. The Netherlands has a head of incidental pressing? Well, we want one too, then.
More to the point, it was a way of illustrating the injured De Jong's importance to the Dutch cause. They are World Cup semifinalists for the fifth time but their task of finally winning the most prestigious prize became exponentially harder when the AC Milan man limped off against Mexico.
He was so integral to Van Gaal's game plan that the chances are that Manchester United will soon be equipped with a leader who can perform similar duties.
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Perhaps that bodes badly for Michael Carrick, United's head of incidental strolling, or Marouane Fellaini, its head of confused wandering, or Tom Cleverley, who lacks the personality to be head of anything. There are few obvious candidates in the squad that the 62-year-old inherits, though the pre-illness Darren Fletcher might have been one.
Van Gaal appreciates the importance of energy in midfield. United has had too little in recent seasons. It is a reason why it has been overrun in the center of the park time and again. Its one-paced midfield has often been subject to frequent unflattering comparisons with Yaya Toure, but it was also telling that last summer Manchester City signed the similarly dynamic Fernandinho. It left United looking still slower in derby defeats.
The 36 million euro signing of Ander Herrera was the first part of the Old Trafford midfield upgrade. A man who was an essential part of an Athletic Bilbao side built around Marcelo Bielsa's pressing principles would seem to fit Van Gaal's ethos.
So, too, another to have worked with the influential Bielsa, Juventus's all-action Arturo Vidal, who played for the Argentine in his days in charge of Chile.
William Carvalho represents an outsider but two in tune with Van Gaal's thinking are Bastian Schweinsteiger, from his time at Bayern Munich, and Kevin Strootman, who may have been deputy head of Holland's incidental pressing but for an inconvenient injury. De Jong himself is a former Manchester City player, but he has been mentioned as well.
It is easy to see why. He has been fundamental to Van Gaal's game plan. His pressing was particularly notable against Spain. This was the coach's response to tiki-taka, his ploy for halting more technically gifted opponents. It showed that he can find a way to win and, for all the talk of total football, his has been an intelligent form of pragmatism in this World Cup.
The fact that Van Gaal has no natural replacement for De Jong was proved when he did not even attempt to find a deputy. Instead, he changed shape against Costa Rica. Playmaker Wesley Sneijder dropped deeper in a reconfigured 3-4-3, forming a partnership with Georginio Wijnaldum.
Neither can hassle and harry quite like De Jong. Nor, indeed, can the slower Daley Blind, who was expected to play in midfield but operated as a wing back.
Against a comparatively defensive, often deep-lying Costa Rica side, there was less need to press; the Netherlands' problem was simply that it could not convert its chances as Keylor Navas produced a masterclass in defiance.
In a semifinal in which it will need to find a way of dispossessing Lionel Messi, it will be imperative. Switzerland's busy, bustling duo of Gokhan Inler and Valon Behrami did its utmost to close him down in the narrow last-16 defeat, even if it was not termed "incidental pressing" by Ottmar Hitzfeld. So, minus his premier destroyer, Van Gaal will have to construct a Messi nullification department. Preferably with a suitably bureaucratic title.