Vijay Singh withdrew from the Wells Fargo Championship because of a sore back on Wednesday, one day after the PGA Tour said it would not punish the Fijian for his admission that he used deer antler spray.
The tour said Tuesday the World Anti-Doping Agency informed it that the spray contains only small amounts of a growth hormone factor 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.
PGA Tour commissioner Tim Finchem said Tuesday that while admission is tantamount to a failed drug test, WADA informed the tour late last week that it no longer considers deer antler spray to be prohibited except for a positive test result. Full story for BostonGlobe.com subscribers.