Video: The Knock That Put Sean O'Brien Out Of The Game

Sean O'Brien was replaced by Tommy O'Donnell midway through the first half of Ireland's encounter with England at the Aviva due to a possible concussion.

O'Brien struggled to get to his feet after a collision with England out-half George Ford. The Irish backrow can clearly be seen stumbling around the 25 second mark of the video above.

Picture credit: Stephen McCarthy / SPORTSFILE