“In alignment with local rules and protocols, the athlete has been transferred to a hotel,” USA Volleyball said in a statement on Wednesday.
The player's name has not yet been officially released.
The athlete is the second member of Team USA to test positive for the virus just two days ahead of the opening ceremonies.
Earlier in the week, the coach of U.S. gymnast Kara Eaker told the Associated Press that the 18-year-old alternate had tested positive for the virus on Monday and will remain in quarantine.
The International Olympic Committee reported 71 people accredited to the games have tested positive for COVID-19, including a growing number of international athletes within the Olympic Village in Tokyo.