Maria Sharapova has pulled out of next week's Cincinnati Open with a left forearm injury.
The 30-year-old withdrew from the Stanford Bank of the West Classic earlier this month after suffering the injury in her first-round match.
The Russian says she is missing Cincinnati "as a precaution for the US Open", which starts on 28 August.
World number 149 Sharapova would need a wild card to play in the main draw in New York.
The five-time Grand Slam champion decided to miss Cincinnati after consulting with event medical staff on Saturday.
Former world number one Victoria Azarenka had already pulled out because of "a family matter".
Men's world number one Murray withdrew last week because of an ongoing hip injury and defending champion Marin Cilic is also out with the adductor injury which has sidelined him since Wimbledon.