The 20-year-old Spieth, who is from Dallas, was selected as an alternate to replace Snedeker in the 18-player field. Snedeker is being cautious after suffering a slight knee surgery when he lost his balance on a Segway (a motorized scooter tourists often use to sightsee) during a corporate outing in Shanghai.
The World Challenge is Dec. 5-8 at Sherwood CC in Thousand Oaks, Calif.
Spieth, whose first round of the year was a pre-qualifier to get into the Monday qualifier at Torrey Pines, shifted from the Web.com Tour to the PGA Tour in March. He quickly earned enough money to get his tour card, winning the John Deere Classic. He finished seventh in the FedEx Cup standings and also played in the Presidents Cup.
The Associated Press contributed to this report.