McGrath primed to master role as Murray back-up
When Joe Schmidt named the squad which would ultimately not prove deep enough to challenge the last four at the 2015 World Cup, there were more out-halves included than scrum-halves.
Far more than a reflection on Ireland's depth at ten, it revealed a worrying disparity in the resources available to him at nine. If Ian Madigan is somewhat of a cause celebre now for being omitted due to temporary exile in France, his inclusion then as a utility player far beyond his usual status as a three-quarters line and out-half deputy also ruffled more than a few feathers.
Ultimately, Eoin Reddan also went to the World Cup but would soon retire, Isaac Boss had played himself out of the squad in the warm-ups and Kieran Marmion, then too slowly adapting his game to Schmidt's template, also missed out on backing up the world leader in the role, Conor Murray.
History would reveal that Murray was one of the few world-class players left standing by the quarter-final stage but even he could not prevent the Puma onslaught that did for Ireland; by that stage, Madigan was compelled to play in Jonathan Sexton's absence, preferred ahead of Paddy Jackson.
The scrum-half experiment has not been replicated since - and Madigan's exile has in any event removed him from the out-half picture while promoting the worthy Jackson - but the issue remains a live one.
Schmidt touched upon it last November, after the bruising battle against Australia which ended with Ireland as depleted as they had been against Argentina, but significantly not beaten, when Marmion was introduced as an emergency winger.
"We are working hard we are trying to make sure the spine has a few more vertebrae in it so we can slip a few more guys in and out of it," he said. "You get a guy like him (Murray) who can control a game like he did in Chicago (against the All Blacks) you don't suddenly slip somebody in and expect him to play well at scrum-half at the same level."
However, the challenge now is that Schmidt must demand that of his squad players - and they must demand it of themselves - with Leinster's Luke McGrath and Marmion jostling to fill that bench berth against Scotland.
Stuart Lancaster has only been with Leinster since the summer but has already been impressed with McGrath's ability to step up to the plate following the retirements of stalwarts Isaac Boss and Eoin Reddan.
"I think he'll be getting close," Lancaster told us recently. "From my point of view, I think he's improved massively since I first arrived.
"I think the main thing he brings is a real athleticism and his ability to not only get the ball away quickly but to bring a running game into the equation, his kicking game has been good. But the best nines have a running threat and a passing threat and a kicking threat, and I think Luke has improved in all three and I think the try that he scored against Montpellier recently was a great example of that.
"The one the previous week, if you remember, he came down the short side and played in Rory O'Loughlin against Zebre, that's just Luke playing heads-up rugby."
And Lancaster has also been enthused by the vocal ability of the player, indicating a forcefulness that adds to his maturity in playing ability. "Nines are the heartbeat of the team, they're the ones who drive everything. I've actually been onto him to be more vocal and Luke has taken on that role well.
"I think he's captained the team, hasn't he, over the last while, which is great experience for him as well. But hopefully in the Six Nations, he has some good scrum-halves ahead of him as well but he's been knocking on the door, I would have thought."
Scannell brothers lead key Munster signings
Dave Kilcoyne, newly-promoted Ireland squad members, brothers Niall and Rory Scannell, Tyler Bleyendaal, Duncan Williams and Darren Sweetnam have all signed contract extensions with Munster
Munster also announced the signings of Chris Farrell, James Hart and JJ Hanrahan - as revealed in the 'Irish Independent' recently.
Kilcoyne's contract extension runs until 2020 with both Scannells, Bleyendaal, ex-Cork hurler Sweetnam and Williams signed up until 2019.
"I've always indicated our intention to recruit Irish-qualified players where and when possible so to secure the young trio of Farrell, Hanrahan and Hart is great for the province and Irish rugby in general," said head coach Rassie Erasmus.
"In addition to being hugely talented they bring a wealth of knowledge with their combined experiences from playing abroad and this will help with our overall squad development.
"I've talked about maximising our potential time and time again. Retaining these players is key to our long-term plans."
James Cronin (finger) has been ruled out for six to eight weeks, while Dave Foley (wrist) will see a specialist this week.