Dutch cut Emanuelson and Maduro from squad
AC Milan's Emanuelson was expected to be the main candidate to replace Erik Pieters, who will miss the finals with a foot injury. Valencia's Maduro only recently returned to fitness after tearing ankle ligaments on international duty in October.
However, Van Marwijk has kept 18-year-old defender Jetro Willems in the squad that will travel to Lausanne on Thursday to prepare for a friendly against Bayern Munich on May 22.
Arjen Robben, Ibrahim Afellay and Stijn Schaars will not be at the training camp because they all have club commitments.
Bayern's Robben is preparing for the Champions League final against Chelsea on Saturday, Sporting's Schaars is getting ready for the Portuguese Cup final on May 20 and Barcelona's Afellay is training with his club for the Spanish Cup final on May 25.
The Dutch host Bulgaria on May 26, Slovakia four days later and Northern Ireland on June 2 in warm-up matches.
Van Marwijk must name his final squad by May 29 for next month's tournament in Poland and Ukraine where the Dutch will face Denmark, Germany and Portugal in Group B.
Goalkeepers: Maarten Stekelenburg (AS Roma), Tim Krul (Newcastle United), Michel Vorm (Swansea City).
Defenders: Vurnon Anita (Ajax Amsterdam), Khalid Boulahrouz (VFB Stuttgart), Wilfred Bouma (PSV Eindhoven), John Heitinga (Everton), Joris Mathijsen (Malaga), Ron Vlaar (Feyenoord), Gregory van der Wiel (Ajax Amsterdam), Jetro Willems (PSV Eindhoven).
Midfielders: Ibrahim Afellay (Barcelona), Mark van Bommel (AC Milan), Nigel de Jong (Manchester City), Adam Maher (AZ Alkmaar), Stijn Schaars (Sporting Portugal), Wesley Sneijder (Inter Milan), Kevin Strootman (PSV Eindhoven), Rafael van der Vaart (Tottenham Hotspur).
Forwards: Klaas Jan Huntelaar (Schalke 04), Luuk de Jong (Twente Enschede), Siem de Jong (Ajax Amsterdam), Dirk Kuyt (Liverpool), Jeremain Lens (PSV Eindhoven), Luciano Narsingh (Heerenveen), Robin van Persie (Arsenal), Arjen Robben (Bayern Munich).