LONDON, June 19 (Xinhua) -- World number one and champion Rafael Nadal's pull-out from Wimbledon resulted in a reshuffle in the men's draw on Friday.
The Spaniard, who won the title for the first time last year after a five-set epic final against Roger Federer, pulled out for the sake of healing his painful knees.
His spot on the top of the draw was taken by Argentine fifth seed Juan Martin del Potro, who had been in the lower half when the draw was initially made on Friday morning.
Del Potro will open his campaign against the world number 49 Arnaud Clement of France and could
face 2002 champion Lleyton Hewitt in the second round.
French Open champion Federer, in pursuit of a record 15th grand slam title, will open his account against Chinese Taipai's Lu Yen-hsun.
However, he will have noted that he could run into Roland Garros runner-up Robin Soderling for the second time in less than a month in the last 16.
American sixth seed Andy Roddick, twice a runner-up in London, was paired with Frenchman Jeremy Chardy and could face del Potro in the quarter-finals.
As a result of Nadal's absence, Germany's Nicolas Kiefer was promoted to 33rd seed and Brazilian lucky loser Thiago Alves was given a place in the 128-strong draw. There will be no top men's seed at Wimbledon this year.
British world number three Andy Murray, hoping to become the first home winner of the men's title since Fred Perry in 1936, is now left as highest seed in the top half following Nadal's withdrawal and is slotted to meet Del Potro in the semis. He faces American Robert Kendrick in his opener.
His quarter of the draw also includes 2008 semi-finalist Marat Safin, who is making his last appearance in London, and his conqueror at Roland Garros, Chile's Fernando Gonzalez.
World number four Novak Djokovic will take on Frenchman Julien Benneteau and was drawn in the same half of the draw as Federer.
Defending women's champion and third seed Venus
Williams, who is the favorite to win a sixth singles title at the grasscourt championships, faces Swiss Stefanie Voegele and could line up against world number one Dinara Safina in the semis.
There could be an all-Williams final showdown at Wimbledon for the second year running since the
American sisters were picked in separate halves of the draw.