The horse is lightly raced because of leg problems. Let's see if he can take the grueling pace it takes to win the Crown. If the races were farther apart you would have to say he is the one to beat.
It's not Leg problems, but Hoof problems. Big Brown has Quarter Cracks.
Which really means in the Horse World Most of the Times, he needs to have less weight bearing !! Try doing that with a Horse.
I don't know how bad his quarter cracks are, but the Higher to the hair line. The Worst it is.
He most likely has a Patch over the area of the Crack.
In Harness Racing ( which I'm sure is the same with Flats ) They are Both Horses. LOL A Horse needs rest between Races. Because of the pounding on the track.
If it gets worst, and the crack moves up the hoof. Sometimes it needs to be cut-out. Then Given Less of a Hoof.
If this is the case, a Bar Shoe is put on. The Bar Shoe is to take pressure off of that Hoof.
My 2 cents is that it is hard for a "Normal Horse" to go Two weeks out, then back again in 3 weeks later.
But I Did say Normal Horse, Big Brown does Not fit as a Normal Horse.
He was a Monster Yesterday.