Baumann has made the Orioles' Opening Day roster, Zachary Silver of MLB.com reports.
Baumann wasn't particularly effective across his first four major-league appearances last year, as he posted a 9.90 ERA and 1.90 WHIP in 10 innings. The Orioles haven't yet announced their fifth starter, but if Baumann doesn't secure a rotation spot to begin the year, he should operate in a multi-inning or piggyback role.