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

https://www.youtube.com/watch?v=0bUNNUk5F4c

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