Following Ireland's World Cup quarter-final exit at the hands of Argentina, Joe Schmidt, who had been shorn of five key players through injury and suspension, decided it was high time to build a squad of greater depth so a more lasting impression could be made in Japan four years later.
n 2016, the Kiwi coach handed debuts to 18 players as Ireland rebounded from an often-deflating Six Nations campaign to record victories over the southern hemisphere big three before the year was out.
The wells at scrum-half and tighthead are hardly overflowing but, besides that, Ireland are well-stocked throughout - no more so than in the back row.
In the extended panel he named for the Six Nations, Schmidt included the Munster trio of Peter O'Mahony, Tommy O'Donnell and CJ Stander - arguably the best-balanced back row in the country - but only the latter could say with any certainty that he'll be in the squad to take on Scotland at Murrayfield on Saturday.
Of Leinster's eight capped loose forwards, Schmidt called on five - Jamie Heaslip, Seán O'Brien, Josh van der Flier, Dan Leavy and Jack Conan.
Conan, as it happens, has just one cap to his name. Having been involved in the larger Six Nations panel in 2015, he made his debut against Scotland in the World Cup warm-up game the following August at the Aviva Stadium.
However, a string of foot and ankle injuries hampered Conan's progression over the next year and, last season, he made just eight appearances for Leinster. Such were the concentrated periods he spent in recovery, the 24-year-old even took up woodwork to fill the idle hours.
While it has been his output in the latter stages of Leinster's return to the Champions Cup quarter-finals - most notably the hat-trick of tries during a rare start against Montpellier - that have caught the eye, he had already banked a run of fine performances beforehand.
In the October win over Connacht at the RDS, which was Conan's first home start for more than a year, he, Leavy and O'Brien proved the standout operators on the day.
He enjoyed a man-of-the-match display in the Pro12 victory over the Dragons, and on St Stephen's Day was one of the few players from the dubiously-selected Leinster team that was thumped by Munster not to dirty their bib.
Conan made his Leinster debut in a league win over Cardiff Blues in February 2014 and, before that, represented Ireland right through the age grades.
The talented back-row did not come from one of the traditional powerhouses of Leinster schools rugby - he was educated at St Gerard's College in Bray, where he first came to the attention of veteran coach Joe McDonnell.
McDonnell looked after the forwards from the Gerard's senior side, while Tony Ward oversaw the backs.
Both men were immediately impressed by the 16-year-old Conan - then in transition year - and drafted him into the senior ranks. It was 2009 and, during his first campaign, Conan provided cover for the back five of the scrum.
McDonnell, who coached Leinster boss Leo Cullen while he was a student in Blackrock College, was sure the teenage Conan was destined for bigger and better things.
"With Jack, on the pitch, he always seemed to be in the right place. Myself and Tony Ward both saw the talent in him straight away," McDonnell recalled.
"He had a nose for the ball, so we brought him into the squad, even though he was only 16. That was quite a good side we had and they went on to win the league three years in a row."
While Conan was rehabbing, Stander and Van der Flier emerged as Test-level competitors - further condensing the logjam of flankers available to Schmidt.
But Conan's obstacles to feature in marquee fixtures are not just limited to the international game. At Leinster, the Teflon Jamie Heaslip, who is soon expected to commit the remainder of his career to club and country, also stands in his way. So, too, does a fit O'Brien, but Conan, who is thought to have turned down a move to Ulster, has always prioritised playing for Leinster.
Furthermore, unless a glut of injuries occur, Conan and others like him are likely to be unhappy spectators more often than not over the next two months.
Ireland's tour of Japan and America next summer can be targeted but, at some stage, he may come to consider his time on the island, particularly with big pay days to be had abroad, which would completely scupper his chances of wearing green.
His old coach would counsel patience to Conan, for now at least. But McDonnell also thinks that his former charge should already be higher up the pecking order.
"I would think at the moment that Jack is a better prospect than Seán O'Brien, because he's carrying so many injuries.
"His best position is No 8, but I also think he could be a seven, depending on what sort the coach wants. When you're in Jack's position, it's about being patient but, after a year or two, if he gets an offer he can consider it."