Jockey Jason Maskiell will front stewards after testing positive to a banned substance.
Racing Victoria stewards received confirmation on Wednesday that a banned substance had been detected in a urine sample provided by Maskiell at Kyneton races on November 6.
The jockey will appear at a stewards' inquiry on Friday into the sample and also the circumstances surrounding the collection of the urine sample.
"No further comment will be made regarding this matter until after Friday's hearing," a Racing Victoria release said.
Maskiell was the champion apprentice in Melbourne in the 2009-2010 racing season.
He was banned for six months in 2011 for a positive drug test.