Northampton wing Chris Ashton has been handed a four-week ban for "an act contrary to good sportsmanship", the Rugby Football Union has confirmed.
The incident took place in Saturday's Premiership defeat at Leicester as Ashton appeared to drag Alesana Tuilagi off the pitch by his hair.
A touchline brawl ensued and Tuilagi and Northampton flanker Tom Wood were both sent off by referee Wayne Barnes.
Ashton will be free to play again on 4 January.
He will miss Northampton's back-to-back Heineken Cup fixtures against Castres and two Premiership games over the festive period against Bath and Newcastle.
Wood and Tuilagi's red cards for striking were deemed sufficient, meaning they were handed no further punishment.
Northampton forward Phil Dowson will also be sidelined for the two weekends of European action. He was suspended for a dangerous tackle on Saracens full-back Alex Goode in the Premiership on 26 November.