Ayumi Morita of Japan pulled out of the U.S. Open on Sunday because of a lower back injury.
The 51st-ranked Morita had been scheduled to play fourth-seeded Sara Errani of Italy, the runner-up at the 2012 French Open and a semifinalist at the 2012 U.S. Open.
Instead, Errani will play 152nd-ranked Olivia Rogowska of Australia in the first round at Flushing Meadows. Rogowska is a "lucky loser" — a player who loses in qualifying rounds but gets into the main draw because someone withdrew. She is 0-2 in the U.S. Open, having lost in the first round in 2009 and last year.
The hard-court tournament begins Monday.