London - Ireland centre Keith Earls is in line to miss the whole of the Six Nations with a knee injury that his province, Munster, said Thursday could keep him out for up to two months.
Earls, who can also play on the wing, suffered his latest injury setback last weekend during Munster's 38-6 European Cup pool win over Edinburgh, limping off after just 25 minutes.
A statement on Munster's website said: "Keith Earls has been ruled out for approximately 6 to 8 weeks after sustaining medial ligament damage to his left knee.
"Earls was scheduled to join his Irish colleagues in camp on Sunday evening after Munster's round 6 Heineken Cup game v Edinburgh. But after picking up an injury to his left knee he was replaced after 25 minutes.
"Keith underwent a scan on Monday before meeting with the specialist yesterday (Wednesday) in Dublin where the injury prognosis was confirmed."
Earls signed a new two-year contract with the Irish Rugby Football Union earlier this week but is now set to miss the national side's first Six Nations under new coach Joe Schmidt.
The 26-year-old Earls has yet to play a Test under the Kiwi after knee problems ruled him out of the November campaign.
Ireland begin the 2014 Six Nations at home to Scotland on 2 February.