Vijay Singh has withdrawn from the Wells Fargo Championship, citing a sore back.
Singh pulled out of the tournament one day after the PGA Tour said it would not punish the 50-year-old Fijian for his admission that he used deer antler spray. The tour said the World Anti-Doping Agency informed it that spray contains only small amounts of a substance that is banned under the anti-doping policy.
The tour had been set to sanction Singh until WADA clarified its position on deer antler spray on Tuesday.
Singh is a past champion at Quail Hollow.