New York - Two-time Grand Slam finalist Kevin Anderson withdrew from the US Open on Saturday due to a right knee injury.
The 33-year-old South African lost the 2017 final at Flushing Meadows to Rafael Nadal and finished runner-up to Novak Djokovic last year at Wimbledon.
Anderson's place in the draw will go to Italian lucky loser Paolo Lorenzi, the US Tennis Association announced.
World No 17 Anderson has not played since his third-round exit at Wimbledon last month.
Injury ruled him out of the recent hardcourt events at Washington, Montreal and Cincinnati.