Leinster prop Jack McGrath has been cited over an alleged stamp during Leinster's 24-11 PRO12 win over Ulster on Saturday.
McGrath was spoken to by the referee after making contact with Rory Best as he lay on the ground during a ruck.
Leinster had a penalty awarded against them at the time.
The citing commissioner has now ruled that McGrath has a case to answer. He will now appear before an independent Pro12 disciplinary committee later this week.
With Leinster due to play Castres in the Champions Cup on 17 January, and Cian Healy already injured, any suspension would present a serious headache for the province and head coach Matt O'Connor.
