O'Brien slapped with one-week ban
Following a review of available camera angles, O'Brien was cited by citing commissioner Dougie Hunter (Scotland) under Law 10.4(a) – for striking with the hand, arm or fist during the World Cup 2015 Pool D match against France at the Millennium Stadium, Cardiff, at the weekend.
O'Brien admitted committing an act of foul play and therefore the judicial officer Terry Willis (Australia) upheld the citing on the basis that the player had committed an act of foul play contrary to Law 10.4(a).
Willis conducted a detailed review of all the available evidence, including all camera angles and additional evidence from the player and submissions from his legal representative.
With respect to the sanction, the judicial officer deemed the act of foul play merited a low-end entry point of two weeks.
The judicial officer considered that there were no aggravating factors.
The judicial officer took into account compelling mitigating factors including O'Brien's conduct prior to and at the hearing, his remorse, good character and clean disciplinary record, and reduced the suspension to a period of one week.
In the context of the World Cup tournament a week equates to one match.
The suspension takes effect immediately, therefore O'Brien is suspended for Ireland's quarterfinal match against Argentina on Sunday, October 18.
He is free to resume playing on October 19.
The player has 48 hours in which to appeal from receipt of the written decision.
O'Brien's unavailability will stretch Irish playing resources even further as Rhys Ruddock arrived to replace the injured O'Mahony and lock Mike McCarthy has been called up to replace iconic skipper O'Connell.
O'Connell had as expected been ruled out earlier on Tuesday with a hamstring injury which has also brought down the curtain on his glittering 108-Test match career.