Black Onyx, a 50-1 shot on the morning line for Saturday’s Kentucky Derby, has been scratched by trainer Kelly Breen. The reason is not yet disclosed, although a vet was seen going into the colt’s stall about 9:30 on Friday morning.

Black Onyx was set to break from post 1, which will now be left open.

There is no change for the program numbers in the 20-horse field.