The Orioles recalled Walker from Triple-A Norfolk on Friday.
With an open spot on the 26-man roster, the Orioles decided to recall Walker from Norfolk to fill that spot. The 31-year-old acted as the 27th man during Wednesday's doubleheader against Boston, but was later returned to Triple-A. With Norfolk, the left-hander has posted a 3.73 ERA, 1.05 WHIP and 34:10 K:BB in 31.1 innings.