Bendtner, 30, hobbled off the field in tears on May 27 after hurting a thigh playing for Rosenborg.
Defender Andreas Bjelland, who plays for Brentford in the English Championship, also missed out because of an injury.
“They resumed training with the squad but we do not think they will be back in shape for the first game,” said coach Age Hareide, in a statement released by the Danish football federation.
Denmark open their World Cup against Peru in Saransk on June 16. They then face Australia before finishing their Group C campaign against one of the favourites, France.
“The match against Peru is very important,” Hareide said. “We are presumably going to be fighting for second place in the group and for that we need to have fit players.”
After a goalless draw away to Sweden on Saturday the Danes have one more warmup game against Mexico in Copenhagen on June 9.
Denmark’s final 23-man World Cup squad:
Goalkeepers: Frederik Ronnow (Brondby/DEN), Jonas Lossl (Huddersfield/ENG), Kasper Schmeichel (Leicester City/ENG)
Defenders: Andreas Christensen (Chelsea/ENG), Henrik Dalsgaard (Brentford/ENG), Jannik Vestergaard (Borussia Moenchengladbach/GER), Jens Stryger Larsen (Udinese/ITA), Jonas Knudsen (Ipswich/ENG), Mathias Jorgensen (Huddersfield/ENG), Simon Kjaer (Sevilla/ESP)
Midfielders: Christian Eriksen (Tottenham/ENG), Lasse Schoene (Ajax/NED), Lukas Lerager (Bordeaux/FRA), Michael Krohn-Dehli (Deportivo La Coruna/ESP), Thomas Delaney (Werder Bremen/GER), William Vitved Kvist (FC Copenhagen/DEN)
Attackers: Andreas Cornelius (Atalanta/ITA), Kasper Dolberg (Ajax/NED), Martin Braithwaite (Bordeaux/DEN on loan from Middlesbrough/ENG), Nicolai Jorgensen (Feyenoord/NED), Pione Sisto (Celta Vigo/ESP), Viktor Fischer (FC Copenhagen/DEN), Yussuf Yurary Poulsen (RB Leipzig/GER)
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