The cause of death wasn't immediately available.
Embiid, a 7-footer out the University of Kansas, has yet to practice or play in the preseason after having surgery on his right foot in June, shortly before the team made him the third overall pick in the draft. He's expected to at least miss a large portion of the regular season.
Coach Brett Brown, general manager Sam Hinkie and forward Luc Mbah a Moute -- like Embiid a native of Cameroon -- skipped the team's exhibition game Thursday night against Boston to be with Embiid at his home in Philadelphia. Assistant coach Chad Iske coached the team in Brown's absence.
"We're all a family here," Iske said. "Obviously, everybody's thinking about Joel and his family at this time. Our hearts and prayers are with him."
Arthur Embiid's exact age is unknown, but Joel, who turned 20 in March, is the oldest of three children born to Thomas and Christine Embiid in Cameroon.