Gordon Elliott is to face a disciplinary hearing in the UK on Wednesday after his horse Zanahiyr tested positive for a banned substance in the wake of a third-place finish in last year's Champion Hurdle.
The Racing Post reported on Tuesday afternoon that Zanahiyr's post-race urine sample contained traces of hydroxylidocaine, a Category B prohibited substance.
Hydroxylidocaine is an active metabolite of lidocaine, a local anaesthetic used in equine medicine. If found guilty, the horse could potentially face disqualification at a hearing of the British Horseracing Authority.
With Jack Kennedy in the saddle, the horse placed third in last year's Hurdle, behind the victorious Honeysuckle and Epatante in second.
According to the BHA's penalty guidance, sanctions can range from fines to disqualification if found guilty.