Leinster flanker Sean O'Brien is expected to join London Irish after the autumn's World Cup.
The 31-year-old back-row forward is understood to have agreed a lucrative deal to join the Exiles, who are on course to win promotion back to the Premiership.
O'Brien would risk his Ireland future with a move abroad, with the Irish Rugby Football Union (IRFU) adopting a policy of only selecting overseas-based players in extreme circumstances.
Ireland selected Johnny Sexton during his two-year stint at Racing 92 between 2013 and 2015, but have not picked anyone based abroad since.
O'Brien's international swansong could well now become this year's World Cup then, after which his IRFU contract expires.
O'Brien has struggled with a string of injuries across a standout Leinster, Ireland and British and Irish Lions career, but still boasts 53 caps for his country.
The combative loose-forward also has five Lions caps to his name, and remains one of Ireland head coach Joe Schmidt's most trusted lieutenants.
Ireland's well-respected player welfare system ensures the IRFU can retain almost all of its top talents, with top stars given more rest than almost all their peers from other Test nations.
Ireland and Leinster would not want to lose O'Brien, but the hugely-admired flanker would not be begrudged a new challenge at this stage of his career.
Former Ireland boss Declan Kidney and ex-Ireland defence coach Les Kiss have partnered up at London Irish, and that link-up has proved central to O'Brien's expected move.
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