Mullins isn't in the lineup for the second game of Monday's doubleheader versus the Blue Jays, Matt Weyrich of The Baltimore Sun reports.
Mullins went 1-for-3 with a double, a walk and a run in the Orioles' 11-5 win in the first game of the twin bill, but he'll begin the second contest of the day on the bench. Colton Cowser will start in center field for the nightcap.