Hull KR captain Joel Tomkins has been banned for two games, with an extra match for a “frivolous challenge” added to his charge for punching.
He was given a one-game ban for a Grade A punching offence in Rovers’ home defeat by London Broncos on Sunday.
Tomkins also received a £500 fine, plus another £500 for contesting the Rugby Football League’s original ban.
Hull KR could be relegated from Super League if they lose their final match of the season at Salford on Friday.
Rovers, Wakefield, Broncos and Huddersfield Giants are level on points and in danger of filling the solitary relegation place.
Tony Smith’s side are second from bottom but will be guaranteed safety if they win at fourth-placed Salford, or if bottom club London lose to Wakefield.
Defeat, however, would leave their top-flight status vulnerable and mean they would have to rely on other results to retain their Super League status.