Vijay Singh out of Phoenix Open after hormone row

Vijay Singh has withdrawn from the Phoenix Open, a day after admitting he used deer-antler spray connected to human growth hormone.

Singh, 49, cited a back injury in pulling out before the first round.

He released a statement at the tournament, saying: "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."