STANFORD, Calif. -- Serena Williams' busy summer schedule caught up with her, making her the latest U.S. Olympian dealing with a knee injury as the Beijing Games approach.
Williams injured her left knee and pulled out of the Bank of the West Classic on Saturday, joining sister Venus and Lindsay Davenport on the injured list.
Williams retired from her match after losing the first set and falling behind in the second set of her semifinal against qualifier Aleksandra Wozniak.
"It was hurting in practice and I didn't really practice too long because it was hurting," Williams said. "After I got off, it was really swollen. I thought that I have to play really fast."
Wozniak will play in Sunday's final against sixth-seeded Marion Bartoli, who beat Ai Sugiyama 6-3, 6-3 in the other semifinal.
Williams lasted only 46 minutes before pulling out of the match trailing 2-6, 1-3. Williams said the injury is different than the one that forced her to undergo surgery on her left knee in 2003 and miss eight months. But that knee has bothered her since, forcing her to drop out of the 2004 Athens Olympics and to miss significant time again in 2006.
But Williams had felt healthy most of this year, playing a busy schedule since winning in Miami in the beginning of April. She played 26 matches in a three-month span that went through her loss in the Wimbledon final to big sister, Venus.
Then she returned home and played for the Washington Kastles of the World Team Tennis league before arriving at Stanford for her debut in this tournament. Williams wouldn't blame her decision to play team tennis on her latest setback.
"You know that risk going into it," she said. "It is what it is. I can't blame that. I just think in general I've been playing a lot of tennis since Miami -- especially for me."
Venus and Davenport have already pulled out of next week's East West Bank Classic in Carson, Calif., due to right knee injuries. Serena said she still plans to go to Carson, but will likely have an MRI before then and could choose to rest up for the Olympics next month.
"I do plan on obviously being at the Olympics," she said. "That's my main goal."
Williams struggled from the start against the 85th-ranked Wozniak and first called for the trainer when trailing 5-2 in the first set. She got the knee heavily taped and came out to finish the set, but appeared to struggle to plant on her injured leg.
"It's unfortunate that she pulled out," Wozniak said. "I think in the middle of the first set she started looking at her leg. I didn't know if it was her ankle bothering her. But at the end it was her knee."
