On Monday, it was confirmed that world number two Alexander Zverev will miss the US Open.
The German suffered an ankle injury in the semifinals of the French Open against Rafael Nadal.
The Spaniard then went on to win the tournament.
Zverev reached the final of the 2020 US Open, where he led 2–0 in sets against Austria's Dominic Thiem.
However, Zverev managed to become the first to lose a 2–0 lead in the tournament since Pancho Gonzalez lost to Ted Schroeder in 1949.
The Serbian Novak Djokovic also risks not being able to compete in the tournament.
He has previously had to withdraw from competitions before the US Open, as he was not allowed to enter the USA due to not having been vaccinated.
American Stefan Kozlov has replaced the star in the main tournament, which begins on Monday, August 29.