Wimbledon champion Marion Bartoli withdrew from the Bank of the West Classic on Thursday because of a hamstring strain.
''During Wimbledon, I developed a strain in my hamstring which has not healed over the past two weeks,'' said Bartoli, the 2009 tournament winner. ''I have been receiving therapy and was optimistic that I would be able to participate. Unfortunately, the injury has not completely healed.''
Bartoli's withdrawal opened a spot for Mallory Burdette in the main draw. Burdette turned pro shortly after the event last year and reached the third round of the US Open.
The tournament at Stanford University in California begins Monday.