Saracens and England wing Chris Ashton could miss the Six Nations after being cited for allegedly making contact with the eyes of Ulster's Luke Marshall.
A disciplinary hearing will take place on Wednesday and Ashton, 28, faces a minimum 12-week ban if found guilty.
The incident happened in the first half of Saracens' European Champions Cup victory at Allianz Park on Saturday.
Ashton was recalled to the England squad by new head coach Eddie Jones last week.
The most recent of Ashton's 39 international caps came against New Zealand in June 2014.
England's Six Nations campaign starts on 6 February against Scotland and ends in France on 19 March.