Bath flanker Francois Louw could be facing a lengthy ban after being cited for making contact with the eye area of Benetton's Marco Fuser, who has been cited himself for biting during the same incident.
Louw, a second-half replacement in Saturday's 23-0 Champions Cup victory at the Recreation Ground, tangled with Fuser at a 77th-minute breakdown, pulling the Italy lock away and then raking his hand across his face.
The veteran South Africa flanker faces a disciplinary committee in London on Wednesday to answer for an offence that carries a low-end sanction of a four-week ban and a top end of 12 to 52 weeks.
Fuser will also attend the independent hearing for allegedly biting Louw, although Irish citing commissioner Tim Lowry has not stated whether the offence was a reaction to or provocation of his opponent's use of the hand.
Reflecting on the incident before the citing was announced, former Ireland captain Brian O'Driscoll described Louw's actions as "foolish".
"As soon as you put your hand across the face of any player...we know how precarious that is," O'Driscoll told BT Sport.
"We've seen it happen recently with Kyle Sinckler. It's just stupidity and foolish from a pretty experienced player. You cannot go near the face area in any shape or form."
Fuser faces the longer suspension if found guilty with biting carrying a low-end sanction of a 12-week ban rising to 24 to 208 weeks for the top end.
Leicester flanker Mike Williams will also appear before the hearing in London after being cited for charging into the ruck and making contact with the head/face area of Racing 92 centre Henry Chavancy.
The offence is alleged to have taken place in the Tigers' defeat in Paris on Saturday and Williams may be facing a ban of two to 10 weeks, depending on the severity.