I think it is possible. He looked good (physically) coming in the race, he just didn't look so good on papers. I bet on Pioneer of the nile, should have done win-place.
I don't know about General Quarters. I like the story, and it would be nice if he wins Preakness, but I don't like the looks of him. (I spent some time working with a vet, so I learned to pick up on suttle soreness signs)
Rachel Alexandra is a good contender also.