Serbian tennis star Viktor Troicki has been given an 18-month suspension for violating an anti-doping rule.
The 27-year-old failed to provide a blood sample during a tournament in Monte Carlo in April this year.
He claimed he had asked permission to be excused the blood test due to feeling unwell, but that explanation was rejected by the governing body.
Troicki is currently ranked 53 in the world and peaked at number 12 in 2011.
His suspension begins immediately and will end on January 24, 2015. Troicki must also forfeit all prize money and rankings points earned at the Monte Carlo Masters.