Williams' Australian Open ends after injury
Three-time champion Venus Williams has pulled out of next week's Sony Ericsson Open in Miami with an abdominal injury.
The 30-year-old world number eight has only played three matches in 2011 and is set to drop out of the top 10.
Williams picked up the injury during January's Australian Open and managed just seven points before retiring against Andrea Petkovic in round three.
Serena Williams will miss Miami as she recovers from a blood clot, while Kim Clijsters is also doubtful.
The world number two from Belgium, who defeated Venus Williams in last year's Miami final, withdrew from this week's BNP Paribas Open in Indian Wells with a nagging shoulder injury.
Venus, who missed much of the latter stages of 2010 with a knee injury, was undefeated in three successive appearances in Miami in 1998, 1999 and 2001.
"I am very sorry to not be playing in the Sony Ericsson Open this year," said the American, who lives 90 minutes north of Key Biscayne in Palm Beach Gardens and considers the tournament her home event.
"It is one of my favourite tournaments on the circuit, especially because it is so close to my home in South Florida. I look forward to returning to the tour soon."