Germany's world number two Alexander Zverev says he is facing a battle to be fit for the U.S. Open following surgery on torn ankle ligaments at the French Open.
Zverev only returned to the practice court last Sunday after the injury he suffered during his semi-final against Rafael Nadal at Roland Garros in June.
He turned on his ankle during that match, screaming in pain when trailing Nadal 7-6 (10/8), 6-6 after three hours of play.
