Barbarians hooker Schalk Brits was slapped with a three-match ban after punching the British and Irish Lions flyhalf Owen Farrell in Hong Kong on Saturday.
It means the Saracens player will miss the first three games of next season.
An International Rugby Board disciplinary hearing in Hong Kong imposed the punishment after Brits was cited by IRB citing commissioner Simon Ryan.
He appeared at a hearing before IRB judicial officer Steve Lewis on Sunday who imposed a three-week ban - effectively three matches.
A statement released after the hearing explained: "The IRB's sanctions for foul play have been established on the basis that a one-week period of suspension would normally result in a player missing one match.
"Consequently, he is suspended from all rugby up to and including the third Premiership match of the 2013-14 season, unless the judicial officer confirms in writing that any pre-season match shall be considered meaningful... in which case such match shall be included as one of the three matches."
Referee Steve Walsh, after consulting television replays, yellow-carded Brits for the seventh-minute incident against his Saracens clubmate Farrell in the Lions' 59-8 victory.