Grigor Dimitrov has pulled out of this week’s Citi Open in Washington due to a flu and sinus infection, ESPN reports.
The withdrawal of the world number nine was announced on Sunday and he is still yet to play since reaching the semi-finals at Wimbledon earlier this month.
The 23-year-old was due to be seeded third for the tournament, behind world number five and six Tomas Berdych and Milos Raonic.
But the Bulgarian will now have to wait to begin his hard court season and he is scheduled to play in the Toronto Masters next week as he aims to gain some form before the US Open, which begins on Monday August 25.
Dimitrov will not be the only notable absentee from the tournament - which is part of the US Open series - as Frenchman Gael Monfils has also pulled out with a knee injury in the men’s draw, while Canada’s Eugenie Bouchard has withdrawn from the women’s draw with a medical problem.
The extent of Dimitrov’s infection is unclear, though it has not been announced that he will miss any more tournaments that he is scheduled to play in.
Dimitrov will be looking to build on a successful year on the tour when he returns to action, as his world ranking has risen 14 positions from 23rd since the start of the year and he has also won three of four singles titles in 2014.
The year began well for Dimitrov, as he reached his first Grand Slam quarter-final at the Australian Open in January, before winning titles in Acapulco, Bucharest and at the Queen’s Club in London.
He achieved the highlight of his career so far when he reached the last four at SW19, beating then reigning champion Andy Murray in three sets in the quarter-finals.
That was followed by a closely fought semi-final against top seed Novak Djokovic, and the Serbian edged his opponent 6-4, 3-6, 7-6, 7-6.
Dimitrov is tipped by some to be a star of the future, and he could further enhance his profile if he is to reach the latter stages of the US Open, where he is so far yet to win a match in the main draw.
There is a chance that he could qualify for the ATP World Tour Finals at the 02 Arena in London in November, should he be able to finish the year ranked inside the top eight, and he will be likely to improve his ranking points total if he improves on last year’s first round exit at the US Open.