After Sunday's 6-3 victory over the Red Sox, Showalter said Johnson will undergo an MRI on Monday in Tampa, Fla.
"They made me aware of it," Showalter said when told that Johnson had relayed the issue to reporters. "We will wait 'til we gather. [Head athletic trainer Richie Bancells] has multiple people, and we'll have that conversation after we get done here. When he gathers all the information. I'm not sure I would be that forthcoming with all that information."
Johnson was hit with Red Sox second baseman Dustin Pedroia's comebacker in the fourth inning of Saturday's game and X-rays were negative on his right foot, with Johnson sporting a walking brace as he met with reporters. He also twisted his left knee on the comebacker, with Johnson saying he felt he got "out of his rhythm" after taking a ball off the foot and he never looked right after that.
Johnson exited after allowing three runs -- all after Pedroia's hit -- over five innings in the Orioles' 4-3 win.