Fergus McFadden: With Gordon D'Arcy and Brian O'Driscoll unavailable, McFadden gets the chance to build on his excellent form last season and, at 13, with the distribution skills of Paddy Wallace on his inside, could get the space to do serious damage. A big game would strengthen calls for final-30 inclusion.
Four years on from the first of his 21 caps, the jury is still out on the leviathan 30-year-old prop. Mike Ross is indisputably the first choice tight-head, but, with Buckley's capacity to play on both sides of the scrum, there is a place on the bench to play for. Needs to handle the squirrely scrummaging of Allan Jacobsen and put himself about in the loose.
There will be precious little settling-in time for the new boy, as McCarthy needs a big game here to cement his claims for the back-row/second-row slot in the final 30. Has the ability and the attitude to thrust himself forward again.
McCarthy's main competition and the favourite for the utility role, Ryan starts in his best position of second-row tomorrow and must impose himself in loose and tight to keep himself ahead in the pecking order.
Not included in the original World Cup squad, Ronan gets a golden ticket to Murrayfield and while he remains an outside bet for the World Cup, a strong demonstration of his natural open-side skills against debutant Ross Rennie would do him no harm at all.