Bieber (7-4) was tagged with the loss Sunday against the Mariners after allowing five runs on 10 hits and two walks while fanning eight across 5.2 innings.
Bieber struck out eight, but he wasn't entirely effective on the mound and gave up season-worst marks in both hits and runs. The right-hander ended a streak of three straight wins, though he still owns a strong 3.28 ERA. He's lined up to make his next start on the road against the Pirates at some point next week.