London Welsh captain Tom May has received a one-week suspension following his Aviva Premiership red card last weekend.
London Irish lock Daniel Leo and centre May were sent off for striking each other in the game which London Irish won 24-9 at the Madejski Stadium.
May lashed out with a swinging elbow and though Leo initially appeared to be defending himself, having grappled May to the floor he struck the Welsh centre with a forearm.
Both players pleaded guilty before Jeremy Summers, who was sitting as a sole judicial officer.
"Leo and May, who were sent off in the Aviva Premiership match between London Irish and London Welsh for striking each other, contrary to Law 10.4(a), are banned from today until January 5, 2015," said an RFU statement.
"They can play again on January 6."
May therefore misses London Welsh's home match with Harlequins on Sunday.
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