"For your reference, the dates involved are February 29, 2020, through March 14, 2020," the team said. "The Reds staff who came in close contact with this employee are being tested and have self-quarantined."
During spring training, the Reds are stationed in Goodyear, Arizona, along with the Cleveland Indians.
MLB canceled spring training and pushed Opening Day back by at least two weeks to limit the possible spread of COVID-19. The league extended its hiatus through the middle of May after the Centers for Disease Control and Prevention recommended Sunday an eight-week halt to events with more than 50 people.
MLB Network's Jon Heyman reported that some MLB executives were hopeful of a start before June.
According to CNN, doctors have confirmed more than 193,000 cases of the coronavirus.
Following the cancellation of spring training, players were permitted to leave their team's facilities and return home but had the option to remain where they were.