Bristol's Alapati Leiua has been banned for four weeks after being found guilty of striking Harlequins' Marcus Smith.
The Samoa winger contested the charge, but an independent disciplinary panel found him guilty of the offence after he was cited following Bristol's loss at Quins on 16 February.
Leiua, who has won 22 caps for his country, will be free to play again for the derby with Bath on 6 April.
He will miss games against Gloucester, Northampton, Worcester and La Rochelle.
"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 chair 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."