Bristol wing Alapati Leiua has been handed a four-week ban after being cited for foul play.
Leiua was reported by match citing commissioner Paul Burke for striking Harlequins fly-half Marcus Smith with his arm during last Saturday's Gallagher Premiership game at The Stoop.
The Rugby Football Union said that Leiua contested the charge when he appeared before an independent disciplinary panel.
"As the player carried the ball into the tackle, he led with his forearm and struck Marcus Smith, the tackler, to the side of the head," panel chairman Gareth Graham said.
"The panel accepted the player's evidence that he had mistimed an attempt to fend off the tackler and had not intended to strike the Harlequins player.
"However, the panel found that by leading with his forearm into the tackle, where the forearm then made contact to the tackler's head, the player had committed a reckless act of foul play that passed the red card threshold. The panel upheld the citing.
"For an offence of striking with an arm which results in contact with the head, there is a mandatory mid-range entry point of a six-week ban.
"The panel found that the player had a good disciplinary record and was remorseful, and was entitled to a reduction of two weeks by way of mitigation."
Samoa international Leiua cannot play again until April 2 and will miss Bristol's Premiership games against Gloucester, Northampton and Worcester as well as their European Challenge Cup quarter-final with La Rochelle.