The incident occurred on the front straight just before the start; the starter was going to go green momentarily. It was thoroughly investigated with interviews and video, so lets not speculate what happened until the stewards report is finished.
I'm very relieved he is (mostly) ok. There hadn't been a diagnosis when I talked to Sherrie late yesterday afternoon. I suspect he will be on here at some point with his own update....
From my standpoint behind him, everything looked good for a start- everybody in line, no one peeking or jumping out. He went sideways pretty quickly into the Fitch barrier at the end of the pit lane.