LEXINGTON, Ky. – Mark Casse has run just one horse in the Kentucky Derby, a 52-1 shot who wound up 10th, but he is quite familiar with Churchill Downs. As a young man, Casse was the leading trainer at Churchill at the 1988 spring meet before branching out into other racing-related endeavors. He returned to training with a vengeance in recent years, having won the Sovereign Award as the top trainer in Canada four times, including 2011.