Durant was ruled out of the exhibition due to injury. Domantas Sabonis of the Indiana Pacers has been named as a replacement, while Tatum will be promoted from the reserves to start in Durant's place.
As one of the top two vote-getters alongside LeBron James, Durant was named a captain and was set to select players for his team in the All-Star Draft.
The 22-year-old Tatum will be playing in his second All-Star Game and making his first start. He's averaging a career-high 25.6 points and 4.5 assists in 27 games this season.