They're probably talking about the herniated disc he had in his neck during spring training. There was a pretty big debate here during that time about whether or not it would adversely affect his stats this year. He's posted good numbers thus far, I'm sure not what people think ARod's capable of however, so the jury's still out. I have him and I've been a bit disappointed but you can't complain too much about what he's done so far.
Bottom line, no new injury to worry about.