ATLANTA (AP) _ Steffi Graf pulled out of the Olympics today because of an injured left knee, robbing Germany of one of its brightest prospects for gold.

``We are extremely sorry that she can't come,'' Heiner Henze, secretary general of the German Olympic Committee, said of the world's top-ranked tennis player.

``Everything is possible in tennis, but the form Steffi was in, she could have won a medal in any case,'' Henze told the German sports news agency SID.

Also withdrawing was the men's top seed, Pete Sampras, who cited an Achilles tendon problem.

Graf won Olympic gold at the 1988 Seoul Games and a silver medal in Barcelona four years ago, when she lost to Jennifer Capriati in the final. The German, fresh from victories at the French Open and Wimbledon, was favored to win at Atlanta.

Germany finished third in the Barcelona medals table and hopes for another top-three finish. Heike Drechsler, the long jump gold medalist in Barcelona, is also a doubtful starter because of a knee injury.

Graf had been wearing a brace in practice and a small white bandage on her knee in matches. She was bothered by the knee injury before Wimbledon.

Last weekend, she helped Germany beat Austria 4-1 in the Federation Cup and reportedly hurt her knee again.

On Monday, she consulted Dr. Hans Passler in Heidelberg, who diagnosed a chronic knee problem and told her to take two weeks off.

Graf initially phoned the German Tennis Federation in Hamburg to announce her withdrawal, and the federation then advised the German Olympic Committee in Atlanta.

Martina Navratilova created a stir during Wimbledon when she said Graf's complaint about her left kneecap may have been planting ``an excuse ahead of time in case she needs it'' to get out of the Olympics.

``If you read the newspapers, you'd think she belongs in the hospital,'' said Navratilova in her role as a commentator on HBO.

``I wish the things she says were true,'' Graf replied. ``I don't like to talk about injuries, or use it as an excuse.''

Also withdrawing today was Julie Halard of France with a wrist injury.

Halard partially tore a tendon in her right wrist in the Fed Cup doubles competition against Spain on Sunday after helping France even the matchup 2-2 with a surprise singles victory over Arantxa Sanchez Vicario.

``It a blow to my morale,'' Halard said. ``I had the Fed Cup and the Olympic Games as my two principal objectives of the season, and now I had to quit both of them at the same time.''

While Halard was considered an outsider for a medal in singles at Atlanta, she and Nathalie Tauziat had a fair shot at an Olympic medal in doubles.