Former Wimbledon champion Maria Sharapova won't play for the rest of the year because of a shoulder injury, the WTA Tour said.

"A nagging right shoulder injury that has kept her out of action since Wimbledon will now keep her out through the end of the 2008 season," the WTA Tour said on its Web site today. The season ends next month, with 2009 competitions beginning in early January.

Sharapova, the biggest earner in women's tennis, also had a right shoulder injury in 2007. She won 22 matches and lost just one at the start of the 2008 season, taking the titles at the Australian Open, Doha and Amelia Island. The 21-year-old took the top ranking after Justine Henin quit the sport in May. Tests showed she had been playing with a "moderate tear" in her rotator cuff since April, she wrote on her Web site on Aug. 1.

"I've been progressing really well, but the recovery is taking a lot longer than I had selfishly planned," Sharapova, a three-time Grand Slam winner, wrote on her Web site. "Therefore, my team and I decided to `shut it down' for the season."

Sharapova was ousted in the fourth round of the French Open by fellow Russian Dinara Safina in an emotional match during which the Parisian crowd turned against her. At Wimbledon, the tournament she won as a 17-year-old in 2004, Sharapova lost her second-round match to Alla Kudryavtseva, who was ranked 152 places below her at the time.

On Aug. 1, Sharapova announced she wouldn't compete in the Beijing Olympics or the U.S. Open because of the tear in her rotator cuff.

Sharapova took home $21.7 million last year, more than any female athlete in the world, according to Sports Illustrated magazine. She pitches products including Canon cameras, Land Rover cars and Sony Ericsson mobile telephones.

Sharapova has been working on her recovery in a clinic in Phoenix, Arizona, she said on her Web site. The Russian said she's been keeping herself fit with running and will start hitting tennis balls again this week.

In the men's game, former top-ranked Roger Federer of Switzerland yesterday announced his season may also be over after he withdrew from the Stockholm Open, which begins Oct. 6. The U.S. Open champion blamed fatigue after a "tough year" that began with him being diagnosed with energy-sapping mononucleosis.