Brazil is set to play France on March 26 in Boston and Croatia on March 31 in Orlando ahead of the tournament in the United States, Mexico and Canada.
Neymar's absence comes after the 34-year-old missed a recent match for Santos FC due to muscle fatigue, scuppering plans for Ancelotti to assess him in person during a scouting trip ahead of the squad announcement.
Neymar, Brazil's all-time leading scorer with 79 goals, has not played for the national team since suffering a serious knee injury in October 2023 and has struggled to maintain a consistent run of matches since returning to Santos last year.
"Neymar can be at the World Cup if he's 100%," Ancelotti told reporters on Monday after announcing his squad. "I didn't call him up because he's not 100%. Neymar has to be training and playing."
The Italian manager, however, has called up 19-year-old Endrick, who returns to international action for the first time in almost a year, and handed a first call-up to Brentford's Igor Thiago as Brazil look to refresh their attacking options.
Brazil will play another friendly against Egypt in June before beginning their Group C World Cup campaign against Morocco on June 13.
Brazil squad:
Goalkeepers: Alisson (Liverpool), Bento (Al-Nassr), Ederson (Fenerbahce)
Defenders: Wesley (AS Roma), Alex Sandro (Flamengo), Douglas Santos (Zenit St Petersburg), Marquinhos (Paris St Germain), Gabriel Magalhaes (Arsenal), Bremer (Juventus), Danilo (Flamengo), Ibanez (Al-Ahli), Leo Pereira (Flamengo)
Midfielders: Andrey Santos (Chelsea), Casemiro (Manchester United), Danilo (Botafogo), Fabinho (Al-Ittihad), Gabriel Sara (Galatasaray)
Forwards: Endrick (Olympique Lyonnais), Igor Thiago (Brentford), Luiz Henrique (Zenit St Petersburg), Rayan (Bournemouth), Joao Pedro (Chelsea), Gabriel Martinelli (Arsenal), Matheus Cunha (Manchester United), Raphinha (Barcelona), Vinicius Jr (Real Madrid)
