England captain Owen Farrell was given a five-match ban on Tuesday after his red card for a dangerous high tackle playing for Saracens on Saturday.
The suspension means he will miss Saracens' European Cup quarter-final at Ireland's Leinster, and any further games in that finals series.
Farrell will also miss several matches in the Premiership, from which the club will be automatically relegated this season after breaching salary cap rules.
But it will leave him free to play for his country in their October and November internationals.
Farrell was sent off after 61 minutes in Saturday's defeat by Wasps after a wild, high tackle that caught replacement fly-half Charlie Atkinson, 18, in the face as the England captain tried to react to his sidestep.
After a four-hour hearing on Tuesday, independent panel chairman Mike Hamlin ruled the tackle was "unacceptable".
"It was accepted by the RFU, the player and the panel that the offending was reckless and not intentional," Hamlin said.
"This was a totally unacceptable contact with the neck/head of Charlie Atkinson as a result of a reckless tackle which had the consequences of him being knocked unconscious and sustaining a concussion.
"This resulted in the panel concluding that this was a top-end offence with an entry point of 10 matches. There were no aggravating features.
"Testimonials provided by Mark McCall, Eddie Jones and the founders of a charity with which the player works very closely were of the highest quality.
"The panel concluded that applying the off-field mitigating factors, notwithstanding his suspension four and a half years ago, the player was entitled to a reduction from 10 matches to five meaningful matches.
"The player is free to play again on October 5."
England travel to Italy in their rearranged Six Nations game at the end of October, then play a "mini" Six Nations, probably also including Georgia, in November.
England have a game against the Barbarians before the Italy match, although Farrell would have been unlikely to feature.