London Irish scrum-half Tomas O'Leary has been banned for three weeks following his sending off in last Saturday's Premiership game against Wasps.
The Ireland international was dismissed by referee Tim Wigglesworth after stamping on Wasps flanker James Haskell early in the second half of the Exiles' 23-20 win at Adams Park.
The Rugby Football Union has revealed O'Leary pleaded guilty at his subsequent disciplinary hearing in London.
O'Leary is now unavailable until March 11, which rules him out of Irish's next two Premiership matches at home to Leicester and away against Exeter.
The Exiles looked in control in the Thames Valley derby after tries for Ian Humphreys and David Paice but Wasps stayed in contact through the boot of Joe Carlisle, and momentum seemed to swing their way when O'Leary was sent off.
Despite being reduced to 14-men Irish managed to hold on for a narrow victory, which saw them move up to ninth in the Premiership standings.
O'Leary's case was heard by a three-man RFU panel chaired by Jeremy Summers.
The result at Twickenham on Saturday?
England to edge it
Ireland to edge it
England by more than 10
Ireland by more than 10
Too close to call