The Guardians transferred Bieber (elbow) to the 60-day injured list Tuesday, Tim Stebbins of MLB.com reports.
The right-hander continues to rehab from Tommy John surgery and isn't expected to be fully ramped up until the middle of summer, so the IL move won't affect his return timeline. Bieber is expected to begin pitching in simulated games at the Guardians' spring training complex at some point in May, after which a lengthy minor-league rehab assignment is likely to follow.