Rosenberg was recalled from Triple-A Salt Lake to start Sunday's game at Seattle, Rhett Bollinger of MLB.com reports.
Rosenberg has made two appearances out of the bullpen for the Halos this season, and he'll make his first career big-league start Sunday. The 26-year-old has a 2.34 ERA, 0.96 WHIP and 36:12 K:BB over 34.2 innings for Salt Lake this year, and he could receive another turn through the rotation with a strong showing versus the Mariners.