Ulster forward Nick Williams has been cited for allegedly striking Cardiff Blues fly-half Rhys Patchell during Friday’s Guinness PRO12 match in Belfast.
Patchell spent the night in hospital as a precaution after being carried off with a head injury sustained in the incident, amid fears of concussion.
Williams was sin-binned after his forearm appeared to connect with the number 10’s head in the first half.
Patchell was treated for 10 minutes before being taken off the pitch.
Referee Marius Mitrea ruled that Williams had gone in carelessly and sin-binned the New Zealander.
Blues coach Dale McIntosh said after the match that the Ulster forward should have received a red card for the offence on Patchell, who has now returned to Wales.
Ulster won the match 36-17 to lie second in the table, two points behind leaders Glasgow.