Boss, a try-scoring substitute against England, was yesterday ruled out of the trip to Murrayfield with a shoulder injury sustained while on Magners League duty for Ulster at the weekend.

Wasps scrum-half Reddan, who has a solitary Test appearance under his belt, fills the vacancy among the substitutes where he will provide cover for Peter Stringer.

Unsurprisingly Ireland coach Eddie O'Sullivan made no further changes to the side that thrashed England 43-13 at Croke Park 11 days ago.

Victory over Scotland would complete Ireland's third Triple Crown in four years and extend their winning sequence against the Scots to seven games.

O'Sullivan said: 'We'll look at how Isaac gets on over the next week before making a decision if he is available for Italy.

'It's an AC joint problem and we're not being overly optimistic about the injury.

'It wasn't the hardest team selection with only Boss' injury to take account of.

'Reddan was an ever-present in the squad last season so we don't lose anything by bringing him in.

'He's a very smart footballer who reads the game very well. He picks, runs and keeps changing the landscape.'

O'Sullivan is expecting a difficult afternoon at Murrayfield where Scotland will be eager to atone for their 37-17 defeat by Italy.

He said: 'It will be an intense game with no quarter asked or given. We'll have to front up. It's exactly as we'd expect.'

Skipper Brian O'Driscoll will lead Ireland for the 36th time, equalling the record set by Keith Wood.
Ireland team: G Dempsey (Leinster); S Horgan (Leinster), B O'Driscoll (Leinster, capt), G D'Arcy (Leinster), D Hickie (Leinster); R O'Gara (Munster), P Stringer (Munster); M Horan (Munster), R Best (Ulster), J Hayes (Munster), D O'Callaghan (Munster), P O'Connell (Munster), S Easterby (Llanelli Scarlets), D Wallace (Munster), D Leamy (Munster).

Replacements: J Flannery (Munster), S Best (Ulster), N Best (Ulster), M O'Driscoll (Munster), E Reddan (Wasps), P Wallace (Ulster), A Trimble (Ulster).