Ireland's Hansen, O'Brien ruled out of Six Nations

DUBLIN :Ireland suffered a double injury blow on Monday when backs Mack Hansen and Jimmy O'Brien were ruled out of their Six Nations title defence through long-term injuries.

Ireland's backline already faced a test without retired flyhalf and captain Johnny Sexton, who they were able to rely on for the past 14 Six Nations tournaments.

Hansen, who started every game of last year's Grand Slam- winning campaign and Ireland's key World Cup fixtures, will be out for three to four months after dislocating his shoulder in the URC Championship last week, his club Connacht said.

O'Brien, who came off the bench to replace Hansen when the Australian-born winger limped out of the World Cup quarter-final defeat by New Zealand, will be unavailable for a number of months with a neck injury, his side Leinster said.

Leinster added that lock James Ryan was withdrawn before last week's URC defeat by Ulster as a precaution and will be further assessed this week before a final decision is made on his availability for European Cup action this weekend.

Reserve Ireland prop Dave Kilcoyne was also ruled out of the tournament last week following shoulder surgery.

Hansen has rarely put a foot wrong since becoming coach Andy Farrell's first choice on the right wing following his debut two years ago, scoring nine tries in 21 games.

Although the 27-year-old O'Brien has only won eight Irish caps to date, his versatility across the back three has made him an important part of Farrell's plans.

Keith Earls' retirement means Hugo Keenan and James Lowe are the only recognised fullback and winger available for selection from the 33-man World Cup squad. Lowe has yet to feature for Leinster this season.

That will likely open up opportunities for Ulster's Jacob