Canada's Milos Raonic has pulled out of the U.S. Open because of an injured glute muscle.
The U.S. Tennis Association announced Raonic's withdrawal on Sunday and said that he will be replaced in the field by Kamil Majchrzak of Poland, who lost in qualifying.
Raonic was expected to take the court on Monday for a first-round match against Chile's Nicolas Jarry at the Grand Slam in New York.
The 28-year-old from Thornhill, Ont., retired early with a back injury on Aug. 7 at the Rogers Cup in Montreal and hasn't played since, hoping to return healthy at Flushing Meadows.
The injury that forced him to withdraw at Rogers Cup started in his glute and crept down his leg, Raonic said after retiring from an all-Canadian second-round matchup against Felix Auger-Aliassime.
Raonic has yet to finish a tournament healthy in 2019.
Montreal's Auger-Aliassime will take on 20-year-old Denis Shapovalov of Richmond Hill, Ont., in the U.S. Open first round for the second year in a row on Tuesday.
Vancouver's Vasek Pospisil and Brayden Schnur of Pickering, Ont., are also entered into the main draw based on their world ranking.