Denis Cheryshev, who scored four goals for Russia at the World Cup, is under investigation for an alleged doping violation.

The 27-year-old, on loan at Valencia from Villarreal, fell under suspicion after his father revealed his son had used growth hormone (HGH) treatment.

The World Anti-Doping Agency told BBC Sport the case was being handled by the Spanish anti-doping authorities.

Cheryshev played five World Cup games as hosts Russia reached the last eight.

The taking of HGH without a therapeutic use exemption can lead to a four-year ban.

Cheryshev's father later said that his remarks, made before last summer's World Cup, had been misquoted by a journalist.

Russian sports daily Sport-Express quoted the player, who began his career at Real Madrid, as saying: "On my side, everything has been honest and I think there will be no problem.

"I think we'd better leave this case in the hands of medics, who have done everything right."