Sampras's decision came only hours after Graf's and is the latest setback for the American who has had a miserable season. Following the death of his coach, Tim Gullikson, earlier this year, Sampras has not won a major tournament, losing at Wimbledon to Richard Krajicek, which ended his dream of a fourth successive title.
The German tennis federation said that a medical examination had revealed a problem with Graf's knee ligaments and her doctor had advised her to take a break of several weeks.
Graf first complained of knee problems last month, when pulling out of the Eastbourne tournament prior to Wimbledon.
The withdrawal is a bitter blow for Graf, who had shrugged off the injury to win her seventh Wimbledon singles title, and had put her off-court problems behind her. Graf's father, Peter, is in prison having been charged with evading millions of marks in taxes on his daughter's income.
Graf took part in the 1984 Los Angeles Olympics, where tennis was a demonstration sport, won in Seoul in 1988 and took the silver medal in Barcelona four years ago. France's Julie Halard has also withdrawn from the tennis with a wrist injury.
Graf's German team-mate, Heike Drechsler, the Olympic long jump champion, denied yesterday that she had withdrawn from Atlanta and insisted that she still hopes to recover from a knee injury in time to defend her gold medal.
In a statement in Atlanta on Monday, she said she would not make the German team for the Games. But now 31-year-old Drechsler says she will give herself until 28 July to decide whether to compete in the Olympic long jump. "If I can jump 6.80 to 6.90 metres in practice, I will go to Atlanta," she said.
Drechsler, gold medallist at the 1992 Barcelona Games, tore a knee ligament in May. The injury healed but the adjacent muscle is not yet at full strength, according to her management. "I will not go to Atlanta as a tourist," Drechsler admitted. "If I go, I do want to fight for medals."
She added she would not rule out competing at the 2000 Olympics in Sydney.Reuse content