Ulster's Will Addison has been banned for four weeks after being found to have made a dangerous tackle during last weekend's European Champions Cup win over Clermont Auvergne.
Addison will miss Friday's Pro14 game against Scarlets, back-to-back European matches against Harlequins plus the Pro14 derby against Leinster.
He was cited for a first-half tackle on Clermont second row Paul Jedrasiak.
Citing commissioner John Byett ruled Addison had a case to answer.
Jedrasiak was forced off injured after the players' heads collided, but referee JP Doyle cleared the Ulster full-back of any foul play after consulting television match official (TMO) Trevor Fisher.
Ireland international Addison did not accept the citing complaint but a disciplinary committee in London ruled the Ulster player had made "reckless contact with Jedrasiak's head in attempting the tackle".
The committee decided that a six-week ban would be the "appropriate" sanction but reduced it to four because of the player's clean disciplinary record.
Addison does have the right to appeal against the decision, which rules him out of this weekend's game, the European ties against Harlequins on 7 and 13 December plus the Pro14 match with Leinster at the RDS Arena on 20 December.
His suspension continues to 22 December, which means he will be in line to feature again for Ulster against Connacht on 27 December.
The former England Under-20 back has emerged as an influential player for Ulster since moving from Sale last year and his absence from a key period in the campaign will be a major blow for coach Dan McFarland.
He narrowly missed out on securing a place in Ireland's World Cup squad this year after earning his second cap in the warm-up win over Wales in August.
Ulster top Pool Three in the Champions Cup after winning their opening two games, while they are second in the Pro14's Conference A following four wins in six matches.