NEW YORK (Reuters) - Ayumi Morita has withdrawn from the U.S. Open because of a lower back injury, tournament organisers said on Sunday.

Morita was due to play Italy's Sara Errani, the fourth seed, in the opening round of the U.S. Open, starting on Monday.

Her place in the women's singles draw will be filled by Australia's Olivia Rogowska.

(Reporting by Julian Linden; editing by Greg Stutchbury)