Scarlets prop Samson Lee has been cited for allegedly stamping during Saturday's 33-26 Heineken Cup victory over Harlequins.
Lee was sent to the sin-bin by referee John Lacey for striking England scrum-half Danny Care with his left boot early in the second half of the clash at Twickenham Stoop.
The 20-year-old will appear before an independent judicial officer in Dublin on Thursday, the European Rugby Cup confirmed, and faces a ban ranging from two to nine weeks if the citing is upheld.
Harlequins director of rugby Conor O'Shea reacted to the incident by saying Lee should have been sent off, but Scarlets boss Simon Easterby felt a yellow card was sufficient.
The red card received by Lifeimi Mafi in the 27-22 defeat at Gloucester means the Perpignan centre must also appear at the disciplinary in Dublin.
Mafi was sent off by referee Leighton Hodges in the 74th minute for a dangerous tackle on Ryan Mills.