Adelaide's leading apprentices were ordered by stewards to provide urine samples at the
Victoria Park meeting on Saturday.
apprentice Matthew Neilson, who's taken the local racing scene by storm in the past couple
of months, was one of the five riders.
The others were the Strathalbyn based Justin Potter, Murray
Bridge's Michael Hoppo and the Morphettville based pair of Ben Claridge and Jason Lyon.
It is the second time in less than six weeks that Hoppo and
Potter have been ordered to provide a sample of their urine for testing.
They were among ten jockeys to be tested at the provincial
meeting at Balaklava on June 26. Their samples returned on that occasion clear.