Ireland have suffered a major blow before their opening Six Nations game against Scotland this afternoon. 

Captain Paul O' Connell has been ruled out of the game due to a chest infection. 

Dan Tuohy starts in his place, while Jamie Heaslip captains the side. 

Elsewhere, there are three changes from the starting 15 that lost to New Zealand in the Autumn series. 

Ulster trio Andrew Trimble, Luke Marshall and Chris Henry are in the side ahead of Tommy Bowe, Gordon D'Arcy and Sean O'Brien respectively.