Saracens captain Brad Barritt has been handed a three-week suspension for his part in the double tackle which left Exeter lock Geoff Parling concussed, but prop Richard Barrington has been cleared to play again immediately.
Barrington was sent off for a shoulder charge on Parling during Saturday's Aviva Premiership clash, while former England centre Barritt avoided any punishment on the day despite catching the former England second row in the face with his arm.
Barritt, who made an apology on Twitter, was cited by the Rugby Football Union for his role in the double challenge which left Parling unable to continue, just 10 minutes into the 13-13 draw at Allianz Park.
World Rugby's new directives on tackling came into force on Jan. 3, with referees ordered to clamp down on anything high or dangerous.
An RFU statement released late on Tuesday following the conclusion of the three-person panel read: "The charges against Sarcens' Richard Barrington for dangerous charging, contrary to law 10.4(g), and teammate Brad Barritt for dangerous tackling, contrary to law 10.4(e) were heard in London.
"The case against Barrington was dismissed and (he) is free to play again with immediate effect. Barritt pleaded guilty and was given a three-week suspension. He is free to play again on Tuesday 31st January.
"Barrington was sent off by referee Ian Tempest in the weekend's Aviva Premiership match between Saracens and Exeter Chiefs for making contact with the head of Geoff Parling of Exeter Chiefs.
"In the same incident, Brad Barritt tackled Geoff Parling dangerously, making contact with his head and was subsequently cited by the citing commissioner."
A statement from the RFU Disciplinary panel, which was comprised of chairman Jeremy Summers, Tom Rees and Dr Julian Morris, explaining the decision read: "Following very careful analysis, the panel found that Mr Barrington had not committed the act of foul play alleged.
"The incident arose out of the specific dynamic of Mr Parling falling unconscious into what would have otherwise been a legitimate contact by Mr Barrington.
"In line with the new sanctions a mid-range entry of six weeks was imposed on Mr Barritt, reduced to three weeks in light of mitigation including his guilty plea."
Speaking on Tuesday afternoon before the panel had convened, Saracens director of rugby Mark McCall outlined the thinking behind the club's intention to contest the red card shown to Barrington.
"For me it wasn't Barrington's fault. It was an accident, but when his shoulder hits Geoff's head, there was going to be trouble," McCall said.
"We've talked about it and we're probably going to fight the charge with Barrington. With Brad we're going to accept the charge.
"In Barrington's case, if you take the time to actually watch what he did in detail, he's in a passive and crouched position.
"He's just unlucky because his job in our team is to target the ball in that situation and unfortunately Geoff's head came a long way to the side and down.
"It happened in 0.18 seconds, so he couldn't have adjusted and avoided it. For me it was just an accident, but in the present climate I doubt it's going to be rescinded."