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OUT: Jonathan Sexton will miss Ireland's final Autumn international against the Pumas - and most of December.

CENTURION Johnny Sexton won't make his 102nd Irish cap this weekend, the captain and out half ruled out Monday for the game against Argentina by a twisted knee.

He will be sidelined for 4-6 weeks, an IRFU statement says, which will also rule him out of Leinster's opening round in the European Champions Cup, at home to Bath on December 11 and away to Montpellier the following week. It would also place him in jeopardy for the St Stephen's Day URC game against Munster.