Leinster
O’Brien made his Leinster debut against Cardiff Blues in September 2008 in the Celtic League. He made his Heineken Cup debut against Castres Olympique in December 2008. He did not feature for Leinster in the 2009 Heineken Cup Final, but evidence of O’Brien’s emergence as one of the most exciting young back-row forwards in Europe came in the form of strong interest from France before Christmas of 2010. The Irish Rugby Football Union, keen to ensure they did not lose such a precocious talent, moved quickly and O’Brien agreed a new three-year deal with Leinster the following January. O'Brien was in outstanding form for Leinster during the pool stages of the 2010-11 Heineken Cup, and he was an integral part of the team that beat Northampton Saints to win the 2011 Heineken Cup Final.
Read more about this topic: Sean O'Brien (rugby Player)