Exercise rider Joel Barrientos takes Kentucky Derby hopeful General a Rod for a morning workout at Churchill Downs Monday, April 28, 2014, in Louisville, Ky. (AP Photo/Charlie Riedel)
An exercise rider takes Kentucky Derby hopeful Hoppertunity for a morning workout at Churchill Downs Monday, April 28, 2014, in Louisville, Ky. (AP Photo/Charlie Riedel)
An exercise rider takes Kentucky Derby hopeful Hoppertunity for a morning workout at Churchill Downs Monday, April 28, 2014, in Louisville, Ky. (AP Photo/Morry Gash)
Exercise rider Abel Flores takes Kentucky Derby hopeful Tapiture for a morning workout in the rain at Churchill Downs Monday, April 28, 2014, in Louisville, Ky. (AP Photo/Garry Jones)
California Chrome is seen from a horse van after arriving at Churchill Downs for the Kentucky Derby in Louisville, Ky., Monday, April 28, 2014. California Chrome has won his last four races by a combined 24 ¼ lengths. (AP Photo/Garry Jones)
California Chrome arrives at Churchill Downs for the Kentucky Derby in Louisville, Ky., Monday, April 28, 2014. California Chrome has won his last four races by a combined 24 ¼ lengths. (AP Photo/Garry Jones)
California Chrome is seen from a horse van after arriving at Churchill Downs for the Kentucky Derby in Louisville, Ky., Monday, April 28, 2014. California Chrome has won his last four races by a combined 24 ¼ lengths. (AP Photo/Garry Jones)
California Chrome walks into Barn 20 at Churchill Downs for the Kentucky Derby in Louisville, Ky., Monday, April 28, 2014. California Chrome has won his last four races by a combined 24 ¼ lengths. (AP Photo/Garry Jones)