Tunisia's Ons Jabeur, who has been struggling with a shoulder injury, withdrew from the US Open on Thursday, officials said.
World number 17 Jabeur was runner-up to Iga Swiatek in the 2022 final in New York.
Jabeur, a former world number two, skipped the Olympics in an effort to preserve her fitness but then withdrew from the Washington WTA tournament at the start of the US Open hardcourt swing.
She then lost in the first round at Toronto to Naomi Osaka before pulling out of the Cincinnati Open last week.
Her slot in the US Open draw passes to Elise Mertens of Belgium. Mertens' spot in turn will go to a qualifier.
