Ranked 10th in the world, Raonic admitted his wrist was ailing after dropping a 6-4 6-4 decision to Frenchman Adrian Mannarino last week in a second-round match at the Rogers Cup in Montreal.
Raonic, 26, has posted a 28-11 mark in 2017.
He is the fourth notable player to recently pull out, joining Switzerland's Roger Federer (back), Scotland's Andy Murray (hip) and Croatia's Marin Cilic (adductor). In addition, Serbia's Novak Djokovic is done for the season with an elbow injury.
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(Editing by Larry Fine)
