Stephen Ferris has been troubled with a knee injury
Stephen Ferris is hopeful that he will have recovered from a knee injury in time for Ulster's Heineken Cup quarter-final against Northampton on 10 April.
Ferris has missed Ireland's opening three matches in the Six Nations and will not feature in the upcoming games with Wales and England.
"The knee is on the mend and I'll see a specialist again next week for another assessment," said the Lions flanker.
"Hopefully he'll give me the go ahead to get back into training soon."
The blindside has been out of action since aggravating a problem with the joint during Ulster's victory over Aironi at the end of January.
In his absence, Leinster's Sean O'Brien has established himself in the number six shirt, producing a huge display in the victory over Scotland at Murrayfield.
Ferris' hopes of returning for the last two championship fixtures against Wales and England have been dashed.
His focus will therefore switch to regaining full fitness in time for Ulster's Heineken Cup quarter-final, the Irish province's first appearance at that stage of the competition since 1999.
"I think it's fair to say we can rule Stephen out of the rest of the Six Nations," said Ireland team manager Paul McNaughton.
On a brighter note for the Irish, scrum-half Tomas O'Leary may come back into the equation for the Wales game having missed the victory over Scotland with a back problem.
"Tomas is continuing rehab with his back and we are not ruling him out of any games at this stage," said McNaughton.
Lions full-back Rob Kearney has been ruled out of the championship as he is still suffering from a knee injury.