Sexton in pole position to get the nod ahead of Jackson
Not since the 2015 World Cup match against France have Ireland had this many front-line players available for a Test match.
This week, like that one, Jared Payne is injured but apart from the centre Joe Schmidt has all of his centrally contracted players available for selection according to yesterday's ultra-positive injury bulletin.
According to skills and kicking coach Richie Murphy, everyone in the 34-man squad trained and that means Rob Kearney, Johnny Sexton, Andrew Trimble, Peter O'Mahony, Iain Henderson and Conor Murray are available.
Josh van der Flier was ruled out earlier this week, while Ultan Dillane is struggling for form on his return from injury and has been left with Connacht but the 23-man matchday squad will have a formidable look to it.
There are a few selection headaches for Schmidt to consider but, while there is a growing clamour for Paddy Jackson to retain the No 10 shirt after doing well in rounds one and two, it seems unlikely.
For all that Murphy said yesterday that Sexton had no "divine right" to come straight into the team on the back of training yesterday, it would be a massive shock if he wasn't named in the starting XV.
Sexton is set to do a full kicking session today, before training again tomorrow ahead of the team announcement. Assuming his calf holds firm, he'll be in the side.
Since Ronan O'Gara retired in 2013, the Leinster star has been out on his own as the pre-eminent No 10.
Starting seven of the last nine Tests has allowed Jackson to close the gap, but while his performances have been good and his kicking-stats strong there are intangible elements that the Ulster pivot just can't match.
"Johnny's been there, he's seen it all. He was a Lions winning outhalf, he's won three Heineken Cups, he's won a couple of Six Nations, so that experience is invaluable for a player," Murphy said.
"Paddy's still only 24, numbers wise they'd add up pretty well, but it's the bits in between. What makes a really good player? Is it what you see or other areas as well.
"It's probably the case that 'what you see' is very similar, it's probably that Paddy is still trying to learn and get better - which he is - at the bits you can't see. It's communication, the reading of the game, the understanding that at one particular moment of the game what's the right decision to make.
"That decision could be based on many different reasons; it could be the conditions, the time of the game, what one defender is going to do different to another... but Johnny's just been in a position where he understands these things a little better than Paddy but the gap is closing.
"Johnny understands the game through his time that he has spent with Joe."
Although he has been plagued with soft-tissue issues, Sexton has played well this season and has a good record of hitting the ground running.