The former world number one Victoria Azarenka will miss the US Tennis Open because of an "ongoing family situation".
The Belarusian only returned to tennis in June after giving birth to her son, Leo, in December.
Azarenka, 28, separated from his father in July and last week she issued a statement saying she could only play in the tournament "if I leave Leo behind".
Misa Eguchi, of Japan, moves into the main draw for the tournament, which starts on 28 August.
"I am sadly unable to compete in this year's US Open due to my ongoing family situation that I am working through," Azarenka said on Monday.
"While I will dearly miss being in New York and playing in one of my favourite tournaments where I have enjoyed some of the best moments in my career, I am already looking forward to being back next year."
Earlier this month Azarenka pulled out of the Cincinnati Open because of "a family matter".
The Australian Open champion in 2012 and 2013, she reached the final in New York in the same two years.
She was knocked out in the fourth round at Wimbledon this year.