Washington - World No 11, South Africa's Kevin Anderson, who withdrew from Washington with right knee pain, has been replaced in the Montreal Masters draw by Poland's 44th-ranked Hubert Hurkacz.
The latest draw posting on the ATP Tour website has removed Anderson from the line-up in favour of alternate Hurkacz as weekend qualifying begins for the US Open tune-up event.
Anderson, a Grand Slam runner-up in each of the past two years, made a third round exit at Wimbledon.
The 33-year-old from Johannesburg, now a Florida resident, has been nursing a right elbow injury for much of the season.
Anderson was the 2017 Washington runner-up to Alexander Zverev on his way to his first Grand Slam singles final at the 2017 US Open, where he lost to Rafael Nadal.
He also reached the 2018 Wimbledon final, where he was defeated by Novak Djokovic.
In January, 6-foot-8 (2.03m) Anderson won his sixth career ATP title at Pune, defeating 6-foot-11 (2.11m) Ivo Karlovic in three tie-breaker sets in the tallest final of the Open era.
Hurkacz, 22, is set to open against 21-year-old American Taylor Fritz, who won their only prior match-up in a quarter-final this year at Eastbourne.