Johnny Sexton ruled out of Six Nations clash with Scotland

Johnny Sexton is struggling with a calf problem and won't be fit in time to make the match. Picture: Getty

Johnny Sexton has been ruled out of Ireland's RBS 6 Nations opener against Scotland after failing to shake off his calf problem.

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Ireland must now face Scotland at Murrayfield on Saturday without their linchpin British and Irish Lions playmaker.

Ulster’s Paddy Jackson should now start at fly-half in Edinburgh, with Munster’s Ian Keatley drafted into the squad as extra cover.