Ireland's Fergus McFadden will not make the cut for Friday night's Guinness PRO12 League match against Munster at Thomond Park.
The versatile back has been making strong progress from surgery to his thumb at the start of the month.
The initial prognosis was that the Suncroft centre-cum-wing would be out of the game for four-six weeks and that he would struggle to put his best foot forward in impressing Joe Schmidt ahead of the kick-off to the Six Nations, away to Italy on February 7.
Since then, he has been recovering really positively and was thought to be a fair bet for involvement against Munster.
This has now been revised and the next available return-to-play date is the New Year skirmish at home to Ulster on January 3.
The identity of those who will be released by Ireland to the provinces is still shrouded in secrecy.
The guesstimate is that most of Ireland's frontline internationals will not be allowed to play in the interprovincials if Shane Jennings' presumption that Conor Murray would not be available to Munster turns out to be true.
Meanwhile, Munster centre Andrew Smith will be out for four-six weeks following a knee operation.
Full-back Johne Murphy (broken nose) and openside Seán Dougall (cut to the head) will be closely monitored tomorrow.
They have not been ruled out of the Leinster match.
Long-term, Ireland second row Donnacha Ryan will start running within a week and Keith Earls is scheduled for a January return from his knee injury.
It is doubtful he will have the time to make an impression on Schmidt soon enough to be considered for the Six Nations.
New Zealand signing Tyler Bleyendall is on course to join the province at the end of January following neck surgery to repair damage done to discs.
Connacht coach Pat Lam will probably have to do without second row Michael Swift and back rower Eoin McKeon.
"Ulster are an enormously proud team and like us, are undefeated at home this season," said Lam.
"It will be a very hard place for us to go and play against a side stacked with quality players.
"If we correct some of the issues we had against Leinster, and add in the belief that we have shown in games this season, it will give us the best opportunity for points."
The western province will travel to Ulster, knowing Ruan Pienaar is unlikely to be risked because of a twisted knee. That will be fine with back-up scrum-half Paul Marshall, who provided a real spark when pressed into service against The Ospreys at the weekend.
The men from the North have been boosted by recent contract extensions for props Calum Black, for three years, and also Andrew Warwick, for two years. It is to their front row they will look to set the standards for set-piece dominance that can be Connacht's Achilles heel.