Callaspo and Miller collided at home plate on the play, and while Miller caught another inning before exiting, Callaspo did not return to the game.
"I think his knee hit right on top of my knee with the slide," Miller said. "He came in pretty hard and kicked it out. It's stiff. I could barely bend down to catch, and thinking about that doesn't help me when I'm trying to call pitches. I don't know if I could have ran if I would have got up again."
Miller is with the Reds in place of Ryan Hanigan, who is out with a sore left wrist. Hanigan is expected to be back this weekend, when the Padres come to town for a three-game set.
Reds manager Dusty Baker said Miller "hurt himself pretty badly" on the play, and the 37-year-old journeyman catcher had a very noticeable limp in the clubhouse following the game.
"If he would have ran me over it probably would have been better for both of us," Miller said with a smile. "He slid in there, his knee came right into mine, and there ain't nothing you can do about it, but he's out."
Jeremy Warnemuende is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.