Knee problems force Na into retirement

WUHAN, China -- Li Na, a two-time Grand Slam champion from China who took tennis in Asia to a new level, has retired due to recurring knee injuries.

The 32-year-old Li posted the news on her microblog Friday, ending a week of intensifying speculation that she would announce her retirement ahead of the new WTA event at Wuhan, her home town.

Li won the 2011 French Open, becoming the first player from China to win a Grand Slam singles title, and clinched the Australian Open title in January in her third trip to the final at Melbourne Park.

She only entered seven tournaments after that, and hasn't played since a third-round defeat at Wimbledon. She withdrew from three tournaments in August, including the U.S. Open, citing a right knee injury.

"Most people in the tennis world know that my career has been marked by my troubled right knee," Li said in a statement posted on social media. "After four knee surgeries and hundreds of shots injected into my knee weekly to alleviate swelling and pain, my body is begging me to stop the pounding.

"My previous three surgeries were on my right knee. My most recent knee surgery took place this July and was on my left knee. After a few weeks of post-surgery recovery, I tried to go through all the necessary steps to get back on the court."

Li set a host of milestones for tennis in China, including being the first Chinese player to win a WTA title and the first to win a major.

Pro baseball

SAN FRANCISCO -- Barry Bonds may yet overturn his obstruction of justice conviction.

Several members of an 11-judge panel of the 9th U.S. Circuit Court of Appeals expressed skepticism over the sole count that baseball's career home run leader was found guilty of following a trial three years ago.

Circuit Judge William A. Fletcher called the prosecution's definition of obstruction "alarming" because Bonds ultimately answered questions before a grand jury about whether he was given drugs to inject himself with, an assertion he denied. Fletcher compared it with lawyers who evaded questions in civil litigation with the intent to mislead, and asked Assistant U.S. Attorney Merry Jean Chan whether that would be criminal behavior. Chan said she believed it would.

"So how many San Francisco lawyers do you intend to put in jail?" Fletcher said. "That is common behavior in civil litigation. Have you just criminalized half the bar here? ... I find your reading of the statute absolutely alarming, and half the bar, maybe three-quarters, maybe all of the bar is in big trouble."

A decision is not expected until next year.

-- From wire reports