Stander stock rises due to the lack of specialist 8s
Injury to Conan reduces Schmidt options at base of scrum as versatile Murphy again asked to fill the void
And then there was one.
As they did at the 2015 World Cup, Ireland will go through the majority of their current campaign with just one specialist No 8 in their squad.
This was not part of the plan this time around, however.
For all that Joe Schmidt has built depth over the last four years, the Ireland head coach has still managed to arrive at a situation where, following one of his two No 8s being ruled out of the tournament, he didn't have a ready-made, natural replacement.
That is not to undervalue the role Jordi Murphy can have in Japan, but he played the majority of his rugby for Ulster last season at openside.
The whole point of him leaving Leinster in the first place - when, ironically, his final game came at No 8 - was to get more time in his preferred number seven shirt.
A foot injury to the luckless Jack Conan has robbed Ireland of an in-form player, who looked like he could have a big impact in the Far East.
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As soon as Conan suffered the setback in training last week, it was only a matter of time before Murphy got the call to pack his bags. One suspects those bags were already half-packed, such is the attritional reality of the modern back-row.
Having only joined up with the squad yesterday afternoon, there is no time for Murphy to kick the jet lag. Instead, he took part in training this morning and will be thrust straight into the action against Russia on Thursday, in a position that is not his natural fit.
Joe Schmidt should get away with juggling his resources for the remaining two pool games against Russia and Samoa, but the Ireland head coach does not want to arrive at a World Cup quarter-final without being able to pick a specialist No 8.
CJ Stander's importance has, therefore, become even greater.
In an ideal world, Stander would not be involved in the Russia clash, but needs must. As Josh van der Flier does not cover enough positions on the bench, Stander will be needed to feature in his third game on the bounce.
Schmidt will hope and pray that the Munster man comes through unscathed because otherwise, he will have a major problem on his hands.
Murphy has started two games for Ireland this year, both at No 8, so Schmidt would argue that he had been preparing for this eventuality all along.
The versatile Murphy had a mixed afternoon against Italy during the Six Nations and while he got another run at the back of the scrum during the warm-up win over the Azzurri in August, his game-time - in what is a specialist position - is, by and large, quite limited.
Spurred on by Conan breathing down his neck, Stander was excellent in the opening victory over Scotland, but that is now firmly in the past. Like the rest of his team-mates, he dipped below his usual high standards in the defeat to Japan.
"I think a good No 8 is someone who tries to process a good work-rate and then links up with the backs," Stander said when explaining the qualities needed to perform at the base of the scrum.
"And be that link up between the backs and the forwards - someone that has a bit of skills and who can slot in anywhere if needs be, and then just be a lineout option and be decent in the scrums.
"Work-rate is important and I think the link between the forwards and the backs, because you're the last voice, so when you go down for a scrum, or a lineout, you're the last voice that the forwards can get from the backs as to what's going on next and what needs to be done. I think that's about it."
Caelan Doris and Max Deegan are next off Leinster's production line, although the latter has already been shifted across the back-row, often to accommodate Doris.
Both Doris and Deegan are outstanding young talents and their time will come.
Even if that is further down the line, Stander is not concerned about the lack of genuine No 8s left in Ireland's World Cup squad.
"With Jordi coming in, he's played a good few games at 8," Stander pointed out.
"He's someone that can literally slot in anywhere in the back five. Pete (O'Mahony) has slotted in there a few times and Rhys (Ruddock) as well.
"Look, we know as a squad that you're going to be called in at some stage to slot into a position and at some stages to put on a bib and train and make the squad prepare well for the game that's at hand. So if needs be, it doesn't matter what happens.
"I think we've got a good squad with a good flow in the back-row anyway where anyone can slot in anywhere."
It's true that Ireland have good viable options across the back-row (Tadhg Beirne has also played at No 8 during his time with the Scarlets), but a World Cup is not the time to be putting square pegs into round holes.
Murphy is an ideal player to be able to call upon for the next two games, but come a potential quarter-final, Ireland need a fit and firing CJ Stander at his best.