Latrell Mitchell will miss the game that looks set to determine whether South Sydney plays finals after receiving a one-match suspension for elbowing Tyson Frizell in the head.
Tensions between Frizell and Mitchell boiled over in the dying minutes of Newcastle's 29-10 win on Sunday when the South Sydney fullback led with his elbow as he moved in to tackle Frizell.
When Mitchell collected the Knights second-rower in the back of the head, a fracas broke out between the sides.
Frizell was uninjured and played the final two minutes but Mitchell went on report and to the sin bin.
Mitchell faced a nervous wait for the match review committee's charge sheet and on Monday morning, he was charged with grade-two dangerous contact.
As a first offence for this season, he faces a one-match ban that could be increased to two games if he chooses to fight his charge at the judiciary.
The suspension is a huge blow for the Rabbitohs, who have the bye next week and must defeat the Sydney Roosters in round 27 to finish the year with a winning record.
Fail to do so, and the Roosters will likely overtake Souths on the ladder and clinch their finals spot, provided they can first defeat the last-placed Wests Tigers this weekend.
It comes after Mitchell was suspended for the Rabbitohs' run to the 2021 grand final for a high tackle on Joseph Manu in the final weeks of that season.
Souths coach Jason Demetriou confirmed after the Knights game that Blake Taaffe would play fullback in Mitchell's absence.
Taaffe most recently filled in when the Rabbitohs lost their marquee man to a long-term calf injury earlier this season.
"It's just silly from Latrell," Rabbitohs coach Jason Demetriou said of Mitchell's shot on Frizell.
"He got his medicine (in the sin bin).
"Blake Taaffe is doing a great job, he's played some good footy for us this year."