Six Nations - Ireland flanker O'Brien likely to miss Six Nations

Ireland flanker Sean O'Brien is likely to miss the Six Nations due to a dislocated shoulder that will keep him sidelined for at least six weeks, his club Leinster said on Monday.

O'Brien, who was part of the British and Irish Lions' team that beat Australia earlier this year, will have surgery on his shoulder after picking up the injury during a club game against Irish rivals Ulster at the weekend.

"Sean is to have surgery this week to repair a dislocated shoulder, which will unfortunately keep him on the sidelines for several months," Leinster said in a statement.

Asked if he would miss the whole of the Six Nations, which runs from February 1 to March 15, Leinster forwards coach Jono Gibbes told journalists "It looks like that" but said no final decision had been made.