Geordan Murphy played for Ireland against Argentina in November
Leicester Tigers' Ireland full-back Geordan Murphy could be ruled out for the rest of the season with a broken foot, BBC Radio Leicester understands.
Murphy was hurt in the Premiership game with Northampton on Saturday and it was thought he had damaged ankle ligaments and would be out for around a month.
Confirmation of a broken foot would be a huge blow to Tigers and Ireland.
Ireland's Six Nations campaign begins on 5 February against Italy and they are already without Rob Kearney.
Murphy had scans after seeing a specialist earlier this week and Tigers director of rugby Richard Cockerill hopes the long-term diagnosis will be kind.
"He certainly won't be fit for this weekend but fingers crossed it won't be too serious. It's really disappointing for Geordan," said Cockerill. "He was coming into some good form."
New Zealander Scott Hamilton is likely to replace Murphy at full-back at club level.
But Ireland coach Declan Kidney has even greater injury concerns, as first-choice full-back Kearney has already been ruled out of Ireland's early games.
Kearney is recovering from a knee injury sustained in the defeat against New Zealand in November and has had surgery.
Luke Fitzgerald may step into the breach for the start of Ireland's Six Nations series.
Hooker Jerry Flannery also looks likely to miss the start of the championship with a torn calf muscle.
A scan revealed the extent of the injury which he sustained after coming on as a second half substitute for Munster against Ulster in the Magners League.
The hooker had just returned to action after a calf injury to his other leg.