Keith Earls looks set to turn down Munster's offer of a new contract and join Premiership champions Saracens on a three-year deal.
The province had been optimistic about their chances of retaining the 28-year-old winger who has kept his counsel on his future, but it is understood that he is close to confirming the move to Allianz Park next season.
Family issues rather than financial motives are believed to be the primary motivation for the Moyross native.
If completed, the move would put Earls' international career at risk. He started every one of Ireland's games at last year's World Cup, breaking Brian O'Driscoll's record for tries scored at the tournament with his effort against Italy.
Having joined up with the rest of the Ireland set-up at Carton House yesterday, he is firmly in the running for a place in Joe Schmidt's match-day 23 for the Six Nations opener against Wales next week.
The union don't have an official policy on overseas players, but to date Johnny Sexton is the only player Schmidt has selected from abroad. That will be tested next season, with Marty Moore, Ian Madigan and, potentially, Earls plying their trade abroad.
While the IRFU may look to put together a last-ditch move to retain the versatile back who has won 46 caps for his country, it is understood his mind appears set on moving.
That comes as a major blow for Munster coach Anthony Foley who is also at risk of losing Simon Zebo to France where Toulouse, Stade Francais and Pau have expressed an interest in the Cork winger.
Earls is steeped in Munster tradition. His father Ger played for the province and for Young Munster and he has been one of their most consistent performers during a difficult campaign to date. Since his debut against Montauban in 2008, he has represented the Reds 121 times.
The news comes hot on the heels of Wasps' confirmation that Moore will join them from Leinster next season on a three-year deal despite his attempts to pull the plug on the move. However, the player had already signed the heads of agreement on his contract and thus had to follow through with the move despite his reservations.
It was an eventful day for Moore who has been ruled out of the Six Nations with a hamstring injury and Joe Schmidt yesterday called Connacht's uncapped prop Finlay Beatham into his squad. It now appears certain that Nathan White will start against Wales, with Tadhg Furlong on the bench.
Johnny Sexton is on track to be fit in time for the Wales game as Leinster said he did not fail the Head Injury Assessment (HIA) at Wasps on Saturday. The IRFU's medical bulletin said the out-half has gone through stages one and two of the HIA process and is due to complete stage three today.
When Munster arrived in Italy on Saturday morning, they did so with the faintest hope of advancing to the quarter-finals, but come kick-off yesterday afternoon, other results meant that their hopes were extinguished, much like they realistically were in Paris three weeks ago.
United Rugby Championship
For the first time in almost 20 years there will be no Irish representation at the business end of Europe's premier club competition. While hugely disappointing it is not the end of the world or, more specifically, the end of professional rugby as we know it in this neck of the woods.
Comment & Analysis
It probably doesn't merit mention - unless you are a prospective or existing international player - but all of the contenders for the Six Nations Championship, with the unhappy exception of the Welsh, named squads where every single player played in their own domestic league with their domestic clubs.