As Rabbitohs players rallied around luckless winger Tyrone Munro and his injured collarbone, Wighton was handed a grade-two charge on Saturday morning.
It means the South Sydney centre will miss next Saturday's clash with St George Illawarra with an early guilty plea, or risk a second week on the sideline if he fights it.
Wighton's hit went unpenalised in the 50th minute of the Rabbitohs' 16-14 defeat of the Dolphins, before Finefeuiaki left the field with a concussion.
In a costly night for Wighton, the former representative star has also copped a $1000 fine for leading with his forearm into a hit up.
Wighton's ban will leave the Rabbitohs without their two left-edge starters from Friday night's win, as Munro also braces for more time on the sidelines.
The winger scored two first-half tries against the Dolphins, but did not return after the break.
He was later seen with his right arm in a sling and, after only one game to begin the year, told teammates he feared another collarbone injury.
A long-term injury would be a bitter blow for Munro, who managed only four games last season as a result of two separate collarbone fractures.
"He's done one in both shoulders now," Souths coach Wayne Bennett said at full-time on Friday.
The Rabbitohs are already severely depleted in the backline, with Latrell Mitchell missing the first month of the season with a hamstring tear and Alex Johnston still recovering from an achilles rupture.
Fletcher Myers will likely be asked to come onto the wing next Saturday in Wollongong, but the Rabbitohs are stretched beyond that.
Playmaker Jayden Sullivan could again fill in at centre as he did on Friday night, with uncapped Auckland-born centre Haizyn Mellars the other back in the Rabbitohs' squad.
English halfback Lewis Dodd is due back from suspension next week, but there is no certainty he will regain his spot from fill-in No.7 Jamie Humphreys.
Meanwhile Munro had been due to begin last season as a first-choice winger at Souths before his injury struggles, and looked poised to finally have extended time in the backline at first-grade level this year.
The 20-year-old has already shown glimpses of his potential and won over the rugby league community by scoring two tries against Penrith days after his mother's sudden death last August.
Stand-in Souths captain Cody Walker said the Rabbitohs were feeling Munro's pain after his latest injury.
"Everyone's disappointed at the club but he's already positive as it is," the five-eighth said.
"I was just talking to him in the sheds, he thinks he's done it again, but he said he'd be right."
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