Indians president of baseball operations Chris Antonetti announced the development Thursday. Indians pitchers and catchers reported to training camp Wednesday in Goodyear, Ariz.
Antonetti did not disclose when the positive test result surfaced.
"During the course of regular testing through the off-season, Shane Bieber did test positive for COVID-19," Antonetti told reporters. "He is in the process of working through return protocols. He had very, very mild symptoms.
"We expect him to get back to the complex at some point within the next few days."
Antonetti also said three Indians pitchers -- Oliver Perez, Nick Sandlin and James Karinchak -- have yet to clear or start the intake testing process required to attend training camp.
MLB COVID-19 protocol requires players to isolate for at least 10 days after a positive test result. Players also are monitored by their respective training staffs and must be medically cleared to rejoin teammates.
Bieber worked out earlier this winter at the team's training complex in Goodyear.
The 25-year-old pitcher had an MLB-best 1.63 ERA and eight wins in 12 starts last season. Bieber also had a league-high 122 strikeouts and finished fourth in American League MVP voting in 2020.
The Indians will face the Cincinnati Reds in their first spring training game at 3:05 p.m. EST on Feb. 28 in Goodyear.