Ryan steps up as he adds calling lineouts to his armoury
Running the set-piece is next step in young star's rapid journey to becoming the complete lock
The emphasis that Joe Schmidt has placed on building the depth of his squad since the 2015 World Cup will be evident in the fact that the group who make the plane to Japan should, in theory at least, be the strongest that Ireland has ever sent to compete for the Webb Ellis trophy.
Up to this point, the Ireland head coach has done an impressive job in his bid to ensure that Ireland are not caught short by key injuries at a second consecutive World Cup.
Having the personnel to slot seamlessly into place when called upon will be crucial, and so too will a player's ability to take on the extra responsibilities that comes with that.
When Ireland lost Paul O'Connell four years ago, it meant that they were shorn of their main lineout caller, Johnny Sexton's absence resulted in their main general not running the backline, while Schmidt was also missing a key defensive leader in Jared Payne.
Since that crushing quarter-final defeat to Argentina, Schmidt has blooded a plethora of fresh faces, whose roles have quickly evolved.
Take Garry Ringrose for example, who has now become a vital cog in Ireland's defence, or Joey Carbery, who has gotten a taste of what it takes to play at out-half in the big games - both with Ireland and Munster.
More recently, however, Schmidt has placed a large focus on his locks being comfortable to call the lineout in pressurised situations.
Devin Toner took over in that regard from O'Connell, and he has done an outstanding job. But his recent injury, which came as a surprise given how ultra-durable Toner is, reiterated the point that Schmidt must be prepared for all eventual outcomes by the time the World Cup comes around.
When you consider that Iain Henderson has also been sidelined with an injury, hypothetically had Ireland begun their Six Nations campaign last weekend, they would have been without their two main lineout callers in Toner and Henderson.
To that end, it has not been a coincidence that Tadhg Beirne has started running Munster's set-piece, while James Ryan has done the same with Leinster in Toner's absence.
There is no doubt that Ryan will be a mainstay in the Leinster and Ireland engine room for the foreseeable future and even more so now that he has added lineout-calling to his rapidly-growing armoury.
It's a skill that many often take for granted and for some locks it takes years to perfect, but Schmidt and Leo Cullen (an excellent lineout caller in his playing days) have been keen to accelerate the process in Ryan's case.
The 22-year-old regularly took on the responsibility for the Ireland U-20s, yet being asked to do so in the Thomond Park cauldron last month was certainly a step up from anything he had faced in the past.
It is interesting to note too that despite the experienced Scott Fardy playing alongside Ryan against Munster, it was the younger man who was entrusted with calling the shots.
With Toner still sidelined last weekend for the superb win over Toulouse, Ryan remained in situ and did a fine job against a technically good lineout.
He has looked totally at ease in doing so and, crucially, it has not hindered other areas of his game - in fact, Ryan seems to be thriving under the added the pressure.
Former Leinster and Ireland second-row Malcolm O'Kelly knows a thing or two about the importance of being an astute lineout caller and, like everyone else, he too has been impressed by what he has seen from Ryan in recent weeks.
"I think he brings pretty much everything you can bring as a lock," O'Kelly enthuses.
"I've seen he's taken over the lineout-calling duties with Leinster.
"Certainly what happened against New Zealand, there's been a push maybe from Ireland or from him to say, 'Okay, it's time for me to step up.'
"That's probably what he wants. A lot of people say, 'Calling the lineout is a lot of pressure', but there are lots of ways to handle it.
"A lot of the lineouts have been designed to help you deal with the pressures of it so I'm sure he'll pick it up pretty quickly.
"A lot of it is luck as well because you're banking on a fella. But it's really just knowing about the working of a lineout and obviously to have a lineout that's structured that you can use effectively and push the opposition to where you want them - to go and free up space because it's just a matter of getting yourself into a space and someone else into a space and put the ball in there, then hopefully you'll get it uncontested.
"For someone like James Ryan, he's a big enough guy. He just needs to work at finding a lineout that really works for him.
"It might just be having one type of lineout: a full or a short lineout that really works for him. He must command that lineout and work it out."
Ryan will be 23 when Ireland set off for Japan, and considering that O'Kelly was only capped for the first time by that age, is pretty ominous in terms of the heights that he can hit. To add to that, most locks don't hit their peak until their late 20s.
Toner is the fulcrum of the Ireland lineout and will be for the coming year as long as he is fit, but Henderson, Beirne and particularly Ryan's emergence as viable alternative options merely highlights the important work that is going on behind the scenes and across the board.