Simona Halep was dropped from the U.S. Open field on Monday because of a provisional doping suspension.
The U.S. Tennis Association announced that Halep, a two-time Grand Slam champion and former No. 1-ranked player, "was automatically withdrawn" when the tournament's qualifying draw was held.
Halep's spot in the main draw for the women's singles tournament in Flushing Meadows went to Taylor Townsend. Play begins on Aug. 28.
During a provisional suspension, a player is ineligible to compete in or attend any sanctioned events.
Halep tested positive at last year's U.S. Open for the banned substance Roxadustat, according to the International Tennis Integrity Agency.
That is a drug approved for medical use in the European Union to treat the symptoms of anemia caused by chronic kidney failure. According to the EU's medicines agency, it stimulates the body to produce more of the natural hormone erythropoietin, or EPO, which has long been a doping product favoured by cyclists and distance runners.
Halep was accused of a second doping offense in May for for irregularities in her Athlete Biological Passport.
She was seeded No. 7 in New York in 2022 and lost in the first round to Daria Snigur of Ukraine.
Halep is a 31-year-old from Romania who first reached No. 1 in the WTA rankings in 2017. She won the French Open in 2018 by beating Sloane Stephens in the final, and Wimbledon in 2019 by defeating Serena Williams in the title match.