Doornbos was driving the backup car, since he crashed his primary car yesterday.
UPDATE:
Robert Doornbos has been cleared for driving by Dr. Michael Olinger. Unfortunately, he is out of cars, unless Graham Rahal (# 02) is willing to let Robert borrow his backup car. Given Robert's 0-for-2 non-crashed cars, if I were Graham, I'd be a little concerned about it.
Doornbos said in a written statement: "I have no idea (what happened.) I'm so disappointed. The guys did an amazing job getting the car ready. We had a good first outing. Everything felt good. We were just starting a run and rear just went on me. I don't know what happened. We'll have to look at the data, but it's disappointing because I wanted to qualify today."