KEY POINTS:
Serena Williams has withdrawn from next week's Los Angeles Classic tennis championship due to a lingering thumb injury that has forced her to pull out of five events since Wimbledon.
The eight-times grand slam winner injured her thumb at Wimbledon in her dramatic fourth-round victory over Daniela Hantuchova before going out to top ranked Justine Henin in the quarter-finals.
Williams has since pulled out of the Fed Cup and tournaments in Cincinnati, Stanford, San Diego and now Los Angeles. Speaking at the San Diego Classic, where his other daughter, Wimbledon champion Venus, is playing, father Richard said Serena was not even practising.