London: Vijai Singh withdrew from the Phoenix Open on Thursday, a day after saying he used deer-antler spray and was "absolutely shocked" that it may contain a banned substance.Vijai cited a back injury in pulling out before the first round.
Vijai claimed on Wednesday night that he had unwittingly used a banned substance and that he was "fully co-operating" with the US Tour, which was considering whether to ban the three-time Major champion.
A statement issued on the Fijian's behalf by the Tour confirmed the revelations in a magazine that Vijai, along with other well-known athletes in American sport, had used the spray.
The supplement contains IGF-1, a "natural anabolic hormone that stimulates muscle growth", which is on the World Anti-Doping Agency's prohibited list and is banned by the major professional sports, including golf. The version Vijai employed was made by a company by the name of SWATS (Sports with Alternatives to Steroids). IGF-1 reacts with the liver to produce human growth hormone, although it is not known if deer IGF-1 works on humans.
Vijai had never tested positive, but then the hormone can only be detected by a blood test and blood tests are not conducted in golf.
Regardless of Vijai's plea of ignorance, the pressure was on the PGA Tour to impose a meaningful sanction.
The Tour's policy says "it does not matter whether you intentionally or unknowingly used a prohibited substance" and for this reason Vijai was facing the prospect of a ban which could stretch to two years and effectively end his top-flight career. He turns 50 next month.
"While I have used deer antler spray, at no time was I aware that it may contain a substance that is banned under the PGA Tour anti-doping policy," Singh said in the statement.