Richard Whitaker is to face the Jockey Club’s disciplinary panel on Thursday after Vicious Prince failed a drugs test at Ripon in May.
A urine sample from the gelding was found to contain morphine – a prohibited substance – after the six-year-old finished second in the Ripon Farm Services Handicap.
The Leeds trainer’s hearing is due to start at 11am.
Gerard Butler will then appear before the panel at their Shaftesbury Avenue headquarters over Cape Unknown, who also had a positive urine test following a race at Bath in July.
The three-year-old gelding’s urine was found to contain hydroxyethylpromazine, which is also a prohibited substance
The 3-1 favourite finished 11th of 14 to Moonmaiden in the Enjoy Pimms At the Races Stakes (Handicap).