Rhys Patchell to miss Cardiff Blues' European Dragons tie

Rhys Patchell was stretchered off the field during Cardiff Blues' defeat to Ulster

Cardiff Blues fly-half Rhys Patchell will miss the European Challenge Cup quarter-final at Newport Gwent Dragons after being carried off during the Pro12 defeat by Ulster.

Patchell spent a night in hospital for assessment after sustaining a head injury in Friday's game.

Ulster forward Nick Williams has been cited for allegedly striking Patchell.

Centre Cory Allen will also miss the Dragons clash after dislocating his shoulder in the same game.

Coach Dale McIntosh says Allen will be assessed and could face weeks on the sidelines.

Patchell, however, should be fit to return for the Pro 12 clash against Glasgow a week Friday.

"He has got to go through normal protocol with concussion," said McIntosh.

"There was a faint chance he could [play against Dragons] but at this time obviously he will not be available.

"It's vital we do not mess with anyone's health."

McIntosh said after the match against Ulster that Williams should have received a red card for the offence on Patchell, who was treated for 10 minutes before being taken off the pitch.

Ulster won the match 36-17 to lie second in the Pro12 table, two points behind leaders Glasgow.