Van Gaal had named a preliminary squad of 32 a fortnight ago but trimmed it down, keeping the uncapped trio of goalkeepers Andries Noppert and Remko Pasveer and the Ajax Amsterdam attacker Kenneth Taylor.
But Leeds United defender Pascal Struijk, who could also play for Belgium, has not made the cut for the matches in Warsaw on September 22nd and Amsterdam, where they host their Belgian neighbours, on September 25th.
The Dutch top their Nations League group with 10 points from four games.
“This is the last chance to see the players at work before we have to name the World Cup selection,” said Van Gaal in a statement.
“As I’ve said before, the preparation time before the World Cup is extremely limited so therefore we have to use all the time we have available. After these games we won’t be together until November 14th, one week before our first game at the World Cup,” he added.
At the World Cup, the Dutch have been drawn in Group A with hosts Qatar, Ecuador and Senegal, who are their first opponents on Nov. 21 at the Al Thumama Stadium.
Squad
Goalkeepers: Jasper Cillessen (NEC Nijmegen), Mark Flekken (Freiburg), Andries Noppert (Heerenveen), Remko Pasveer (Ajax Amsterdam)
Defenders: Nathan Ake (Manchester City), Daley Blind (Ajax Amsterdam), Matthijs de Ligt (Bayern Munich), Stefan de Vrij (Inter Milan), Denzel Dumfries (Inter Milan), Tyrell Malacia (Manchester United), Bruno Martins Indi (AZ Alkmaar), Devyne Rensch, Jurrien Timber (both Ajax Amsterdam), Virgil van Dijk (Liverpool)
Midfielders: Steven Berghuis (Ajax Amsterdam), Frenkie de Jong (Barcelona), Marten de Roon (Atalanta), Davy Klaassen (Ajax Amsterdam), Teun Koopmeiners (Atalanta), Kenneth Taylor (Ajax Amsterdam)
Forwards: Steven Bergwijn (Ajax Amsterdam), Memphis Depay (Barcelona), Cody Gakpo (PSV Eindhoven), Vincent Janssen (Royal Antwerp), Wout Weghorst (Besiktas).
