Cronin is ready to make a major impact when the call comes
There is no substitute for hard work and no substitute who works harder than Sean Cronin.
Except don't tell him he's a substitute. Or an impact player. Or a replacement for that matter. Finishers, the mot du jour, as coined by Eddie Jones, might suffice. A bit more prestigious, that.
"I don't know, I might have a word with the press guy here and see if we can put finishers or something," he laughs.
Even the playbill sets the stall out; all of Ireland's starters are lined up in broad, sweeping capital letters; the eight, erm, replacements, are forlornly bereft of such eloquent grandeur.
"It really annoys me the fact that all the lads' names are really big and then the replacements are tiny at the bottom.
"If the names were a small bit bigger I'd be happier with that."
Rory Best, captain, is this team's Hamlet; Cronin a mere gravedigger, it seems.
The sub teacher always waiting for the call.
This Saturday will mark the 28th successive occasion - when he has been fit and ready to start, or at least finish - that he has been named on the bench.
Such is the life of the perennial understudy. Always second in line for his country, even if never content to remain second best.
So devoted is English head coach Jones' faith in his finishers, even the official RFU teamsheet lists them as such.
"I find it funny. Good old Eddie. It makes a bit of sense, doesn't it? That's something that we're looking for here," he says.
"That's what we're trying to provide for him. For guys that are coming off the bench just to fit in and add value."
Cronin always comes off the bench when he is on it and always adds value, of that there is little doubt.
Of course, he would dearly cherish starting; not necessarily a sniping figure, waiting in the wings for the lead actor to be struck down by a sudden attack of glandular fever.
Then again, even when Best was injured and broke his sequence of 52 successive starts two springs ago, cruel fate decreed that the second Best would also be ruled out when he ripped his hamstring clean off the bone.
Even his status as second man in has not always been franked; he has been peremptorily culled from a Six Nations squad the week after a typically barrelling bench effort.
He has been dropped similarly during the middle of a World Cup tournament. Still he soldiers selflessly on.
Last November, during a time when he normally hoovers up those cherished starting slots with his name in lights, he was omitted from the squad entirely. Not even third choice, ye Gods!
"I held my hands up and said the other guys who got it were playing better rugby than me at the time," says the player whose 58 cap career features just nine starts in a nine-year career.
"Other guys could have sulked - but I said to myself, use this as a positive. Get back playing."
You suggest, colloquially, it might have been a well-directed kick to his rear end. He agrees.
"They were pretty honest. They said, 'look, we just didn't think you hit the ground running, you haven't been playing too well whereas other guys were playing really well'. It was a good motivator for me," he adds.
Cronin's patience abides. The ultimate closer. There's no substitute for that.