The Orioles sent backup catcher Craig Tatum for an MRI on his sore right knee, and they're waiting for the results.
The knee started bothering Tatum during Sunday's start against Tampa Bay at Tropicana Field.
Manager Buck Showalter doesn't believe that Tatum will need to go on the disabled list, "but that could change depending on what the MRI shows," he said.
Showalter was going to use Jake Fox as his designated hitter tonight, but Tatum isn't available. Fox is needed as a potential backup if Matt Wieters is removed for a pinch-runner.