A back injury forced Vijay Singh to withdraw from the Wells Fargo Championship at Quail Hollow Club in Charlotte, N.C., the PGA Tour announced Wednesday.
Singh, 50, made news on Tuesday when he was cleared by the tour of violating its drug policy for using a deer-antler spray that could contain a banned substance. He said he was unaware when he used the spray that it potentially contained a performance enhancer connected to human growth hormone.
The World Anti-Doping Agency no longer prohibits the use o deer-antler spray and the PGA Tour dropped its case. Singh had appealed the tour's sanctions against him in February.
Singh, a three-time major champion, won the Wells Fargo event in 2005. He joins six others, including Dustin Johnson, who have withrawn this week from the tournament.