Baumann was recalled from Triple-A Norfolk on Thursday.
Baumann made the Orioles' Opening Day bullpen but has spent much of the season in the minors, posting a 4.91 ERA and 8:6 K:BB in 11 innings at the highest level. He's remained a reliever in the minors, where he's struggled to a 7.71 ERA across 16.1 frames. That suggests he could continue to pitch out of the pen going forward even though it's starter Bruce Zimmermann who he'll be replacing on the active roster.