Serena Williams on Tuesday withdrew from next week's JP Morgan Chase Open at the Home Depot Center in Carson, the third tournament she has pulled out from in the last 10 days.
In announcing the move, WTA officials cited the same strained left quadriceps that forced Williams out of this week's Acura Classic at Carlsbad, Calif.
The injury was confirmed Monday when Williams had an MRI exam in Los Angeles and was advised by doctors to rest. She cited unrelated knee pain in pulling out of the Bank of the West Classic at Stanford last week.
In a written statement, JP Morgan Chase Open tournament director Gus Sampras wished Williams a quick recovery and said he was "disappointed that Serena is unable to play in our tournament."