If anyone didn't watch the race live, an interesting thing is Barbaro left early and broke through the gate when they were still closed before the race started, and the gates are held together by strong magnets and take a lot of force to open. He went back walking fine, but he smashed his front knees into the gate and it was thought he might have been in pain and favoring other legs or off rhythm.
I've seen those replays over and over. When I posted about the "knees" comment I heard, it was that Barbaro had fallen to his knees at some point, but I do think he was mounted at the time and it was possibly pre-Derby.
It was just race people talking and someone said they had seen it happen - but I got the impression it wasn't yesterday.
If I run across the comment again, I'll post it here. It wasn't about his knees hitting the gate, I know that. All those same people said he didn't - but I do know it's still a possibility, too.