I preface this by saying you can't read into body language but I think Mankins cart off could be precationary/minor (relative to a need for the cart). He was on the ground getting looked at. looked like his knee. they brought the cart over but he didn't need to be lifted into it, he was helped up and walked to the cart a few feet or so on his own. He didn't look depressed and acknowledged the crowd when they cheered him. I didn't see what happened but oddly enough it seemed he hurt himself on the lap. Maybe someone else so what actually happened.
Ohrenberger got carted off too but he definitely looked heat related. Now that I think about if they were looking at a cramp and not his knee maybe that is the case but this might even be more optimistic than my above paragraph.
