The Orioles recalled Selby from Triple-A Norfolk on Sunday.
The 26-year-old was acquired from the Royals in early July and will now receive his first look in the big leagues with the Orioles. Selby also spent time with the Pirates earlier in the season, but he's struggled at Triple-A between all three organizations with a 5.79 ERA, 1.35 WHIP and 42:16 K:BB over 32.2 innings.