Time for Chat over for Seán
Hooker Cronin wants to win a major trophy as Blues starter
This could come down to the set-piece. Racing 92 established their superiority over Munster in The Champions Cup semi-final with a barnstorming series of opening blasts from their bulging big men.
Every time Munster threatened a legitimate recovery they were thwarted at the the lineout where Nenagh's Donnacha Ryan called all the right shots for his new club.
The fact veteran Dimitri Szarzewski, 35, has been ruled out with injury redoubles the responsibility on their first-choice hooker Camille Chat, with journeyman Ole Avei as his back-up.
The hooker is dynamite in the loose where it is not unusual to see defenders bounced backwards.
It can be inspirational to see Chat rampaging in a manner not dissimilar to our own Keith Wood.
It is at the lineout and in the scrum where the France international will have to drill down on his core duties against Leinster's eight.
The 22-year-old is still making his way in the game and, like all in his position, throwing issues in the past that have caused concern for the jumpers in front of him.
There is a reason why Leinster have pointed to Racing's defensive lineout as a real weakness.
They believe they can go after Chat on Racing's darts.
The height of Devin Toner, athleticism of James Ryan, and nous of Scott Fardy will be out to plant the seeds of doubt early for Chat.
Limerick man Cronin is just as dangerous in the loose as the Frenchman.
He just does it by using his searing pace to get beyond enemy lines rather than running over the top of someone.
The 32- year-old is remaking his reputation in the autumn of his three-province career.
Just a few short months ago Ireland coach Joe Schmidt left Cronin out of the squad for the November internationals.
In one swift move, he had plummeted from second choice hooker behind Rory Best all the way below Rob Herring, James Tracy and Niall Scannell, who was out injured, to fifth choice.
He admitted to coming back from injury, lacking in match sharpness and just not playing well back then.
"It was probably the kick up the arse I needed at the time to refocus," he said.
He went back to his club and worked on his game, honing the tools he was missing, physically and mentally.
"It gave me a chance to play here. You have those ups and downs. I think I'm on a bit of an up now, which is good."
Cronin began his personal European journey this season as back-up to James Tracy against Montpellier last October.
It was the last time he sat out the first whistle, convincing coaches Leo Cullen and Stuart Lancaster that he was more than the impact animal for Ireland.
At the centre of Cronin's career disappointments has been a suspicion that his scrummaging has not always been a strength.
The considerable assistance of scrum coaches Greg Feek, at Ireland, and John Fogarty, at Leinster, has been a consistent force in his work life.
Of course, the similarity in faces between the club and international set-up gives Cronin extra security.
Loose-head props Cian Healy, Jack McGrath and tight-heads Tadhg Furlong and Andrew Porter out in Carton House as well as Michael Bent at the club has seen him develop this part of his game.
"I looked to have more consistency in general so I could bring the whole package together," he said.
"In terms of that, I think I'm probably performing to the best of my career in terms of my scrummaging."
There have been many positive stories to come out of Irish rugby this season.
The rise of the new generation has been a wonder, probably the reason between being in Bilbao and being knocked out by Saracens.
But there is no one who has been dropped all the way down to fifth choice for his country and climbed back to Six Nations glory.
This has been a season of recovery and rejuvenation for Cronin.
It will only be really complete when he starts what James Tracy will finish.
- Champions Cup final Leinster v Racing 92 (Today 4.45, SSAction/BT Sport 2)