The team is contemplating if Posada needs X-rays.
"I don't think it will be a DL," Posada said after the Yankees' 8-3 win.
Orioles starter Jeremy Guthrie, who injured Mark Teixeira with a hit by pitch in spring training, nailed Posada's right knee with a 94-mph fastball, causing the Yankees catcher left the game in the bottom of the inning.
"You don't want him to hit people," said Girardi, who didn't think the pitch was on purpose. "I'm not going to tell Guthrie how to pitch. He is going to pitch the way he is going to pitch. I respect him. As I said, when our guys are getting plunked, I'm not going to be happy about it, because we don't have Posada probably [on Thursday]."
In the Orioles clubhouse, Guthrie blamed his control.
"I'm not a pinpoint pitcher," Guthrie said. "If I were, I would be a much better pitcher."
Guthrie added: "I'm apologetic to Jorge if he is to miss any time for [me] yanking a pitch and hitting him."