Cincinnati - World number 10 Milos Raonic of Canada withdrew from the ATP Cincinnati Masters on Tuesday with a left wrist injury, joining a list of high-profile absentees at the US Open tuneup.
Raonic blamed the sore wrist for his first-match loss last week in Montreal to France's Adrian Mannarino.
"My wrist injury has not healed," Raonic said. "I always play well in Cincinnati and will miss the great fans."
The 2016 Wimbledon runner-up becomes the latest in an all-star lineup to skip the US Midwest hardcourt classic with the year's final Grand Slam event less than two weeks away.
Other men's stars missing this week include Roger Federer due to a sore back, world number one Andy Murray with a hip injury, Novak Djokovic, out for the year with an elbow injury, and Stan Wawrinka, missing the rest of the season with a knee injury, as well as ninth-ranked Kei Nishikori and 2016 Cincinnati champion Marin Cilic.
On the women's side, Serena Williams is absent while pregnant and Maria Sharapova, who received a US Open wildcard on Tuesday, is sidelined by a forearm injury.