Baumann will start Saturday's game against the Astros, Roch Kubatko of MASNSports.com reports.
The 27-year-old rejoined the Orioles on Sept. 11 and has made two appearances out of the bullpen, but he'll start Saturday with Tyler Wells (shoulder) on the injured list. Baumann covered two frames in each of those outings and is unlikely to have a full starting workload.