The Orioles were also expected to activate Manny Machado from the disabled list Tuesday. However, that move will also have to wait at least another day. Machado had surgery in October to repair a torn medial patellofemoral ligament in his left knee. He injured the knee Sept. 23 against Tampa Bay.
Machado was not concerned about the weather and said he was ready to play Tuesday despite the wet conditions.
"I'm here to play baseball," Machado said. "If it is snow, if it is rain, if it is whatever. I've been down in Florida with a lot of sun. So I'm just here to play baseball, whatever the climate throws out there, I'm going to go out there and play no matter what."
The postponement was the second in two weeks for the Orioles, who have also played 11 day games this month. At this point, the players are prepared for anything.
"This month hasn't been an ideal schedule for us, dealing with the night games and then the morning games following," shortstop J.J. Hardy said. "It's been a struggle, but we're staying afloat. I don't think anyone is really pulling away. Overall, we've gotten past the pretty tough part of our schedule, and it's time to move on."
If the Orioles and Pirates do not have another rainout Wednesday, the original starters for that game could also be pushed back. Baltimore righty Bud Norris (1-2, 4.44 ERA) was expected to face Pittsburgh right-hander Brandon Cumpton (0-1, 2.57 ERA).
Todd Karpovich is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.