Joseph didn't fly to Australia with the national team earlier this month, though it was reported that the 28-year-old would join the side in time for the tournament.
With Joseph apparently bowing out, Orlando Magic center Khem Birch is the only active NBA player left on Canada's World Cup roster. Miami Heat center Kelly Olynyk pulled out after suffering a knee injury during an exhibition game against Nigeria, while RJ Barrett, Jamal Murray, Chris Boucher, Tristan Thompson, and Andrew Wiggins all withdrew from consideration.
The reason for Joseph's apparent withdrawal is unclear. He signed a reported three-year, $37-million contract with the Kings in July following two seasons with the Indiana Pacers.
In order to qualify directly for the 2020 Olympics in Tokyo, Japan, the Canadian team needs to finish as one of the top two squads from the Americas at the World Cup. The United States, Brazil, Venezuela, Argentina, Puerto Rico, and the Dominican Republic are also competing at the tournament.
The FIBA World Cup will begin Aug. 31 in China.