Racing Victoria stewards have confirmed apprentice Tom Sadler has returned a positive urine sample to a banned substance.
Sadler was stood down from riding by stewards on Tuesday, pending the results of the confirmatory sample which was received on Thursday.
The sample was provided by Sadler at the Swan Hill meeting on July 27.
Stewards are continuing their investigations.
Sadler rode a winning double at Flemington last Saturday.
It's the latest setback for Sadler who returned to riding in June after being sidelined with a fractured fibula.