St Helens will be without influential scrum-half Luke Walsh for Friday's Super League derby with Wigan at the DW Stadium, live on Sky Sports 2.
The Australian was given a two-match ban and £300 fine after being found guilty of a dangerous throw when he appeared in front of a Rugby Football League independent tribunal on Wednesday evening.
Walsh was sin-binned for the dangerous tackle on Catalans Dragons half-back Lucas Albert during his side's 39-16 Super 8s victory over the French club at Langtree Park on Friday and was subsequently charged by the RFL's match review panel with a grade C offence.
The player was eligible for an early guilty plea but St Helens chose to fight the case, coach Keiron Cunningham arguing that there was no intent to injure and that the sin-binning ought to have been sufficient punishment.
St Helens forward Luke Thompson was also given a two-match ban and a £300 fine after being found guilty of an illegal shoulder charge on Catalans second rower Justin Horo in the same game.
Thompson, too, denied the offence and Saints must now decide whether to launch an appeal, which would be heard on Thursday.
Meanwhile, Featherstone forward John Davies will miss his club's next two matches in the Super 8s Qualifiers through suspension.
The former Castleford back rower submitted an early-guilty plea to a grade C offence of using foul and/or abusive language to a match official during Sunday's 62-16 defeat at Huddersfield and was given a two-match ban.
Davies, who was sin-binned in the second half by referee Gareth Hewer for dissent, will sit out Rovers' Qualifiers against Leigh and Batley.
Leigh forward Jamie Acton was given a four-match ban after pleading guilty to a grade C offence of "other contrary behaviour" during his side's 32-26 win over Salford.
A grade C offence normally carries a suspension of two to three matches and the disciplinary panel say they went outside the sentencing guidelines because of the player's previous record, the deliberate nature of the offence and the
potential to cause serious injury.