The astonishing elevation comes less than 100 days after the 20-year-old Cork dual-star arrived in Melbourne with little knowledge of Australian Rules and no guarantees of winning a spot on the Blues' roster.
Ó'hAilpín was yesterday named in Carlton's 28-man squad to play Geelong at Optus Oval tomorrow, and according to the Melbourne Herald-Sun, is expected to make the cut of 24. He will be given the No 38 shirt.
The fast-tracking of the 20-year-old is being viewed as one of the most spectacular chapters in the long-running Irish experiment by AFL clubs. Blues coach Denis Pagan said Ó'hAilpín had "defied logic" since flying in to Melbourne at 6am one morning last November and heading straight to Optus Oval for a training session.
"Five months ago he wouldn't have known the difference between a football and an Easter egg," Pagan said yesterday.
Carlton placed Setanta on its rookie list and has allowed him to play in several practice matches this year.
A brilliant performance in a defensive role for the Carlton-affiliated Northern Bullants against Coburg last Friday convinced Pagan and his match committee to play Ó'hAilpín tomorrow.
"He has defied logic since he has been here," Pagan said. "He shouldn't have handled the football the way he did, shouldn't have been able to bounce the ball.
"He did that virtually first time. He played very well last week. We will have to see what happens, whether he makes the final squad or not."
His athleticism, stamina, pace and courage first attracted Carlton's overseas contacts, who alerted then-Blues recruiting manager Shane O'Sullivan.
O'Sullivan liked what he saw via video and invited Ó'hAilpin to train with the club before Christmas.
The pursuit of Ó'hAilpín was in part the result of severe draft penalties imposed on Carlton by the AFL for salary-cap breaches.
Herald-Sun columnist Mike Sheahan writes in today's paper: "It is hard to imagine any one of the tens of thousands of Irish boyos who have made a new life here making a quicker impact than the exotically named Setanta Ó'hAilpín.
"The hurling star from Cork will further enrich the ethnic flavour of the mighty Carlton Football Club when he represents the Blues in the Wizard Cup at Optus Oval tomorrow.
"Yes, it's only football, and, even more so, it's only a pre-season fixture, but it is a monumental achievement in the context of sport. This kid didn't start handling a football with any purpose until November.
"No wonder there were emotional scenes at Optus Oval yesterday when coach Denis Pagan announced that 'Carlos' was in the squad and would play against Geelong. Spontaneous and warm applause from the players, hugs and kisses from himself.
"The Blues were prepared to rookie-list Ó'hAilpÍn, hoping, dreaming, he might repay the faith in two or three years," writes Sheahan.
"There is no football code in the world that is played with a ball as contrary as the Australian ball. Only the most talented of home-grown Australians master it; most of us revered it, yet never really understood its mysteries. Here's a boy who arrived in Australia from Ireland round about Melbourne Cup time who is playing at senior level already. Perhaps Dermot Weld trained him on the quiet at home."
Ex-Dublin star, Jim Stynes, a 1991 Brownlow Medal winner in Melbourne, said last night that Ó'hAilpín's pace and size had helped his sporting transformation.
"To come all that way and for this to happen is just brilliant. The good thing about this is that Denis knows what he's doing, and at the moment for him (Ó'hAilpín) it is all about gaining experience, which he will do.
"When you see these things happen, it is normally 'Oh, here's another Irish kid, we might see more of him in two or three years' time'. What's happened here is very, very quick."
Because of his rookie status, Ó'hAilpín must wait for a long-term injury to a team-mate before he can be promoted to the senior list. But Pagan said only time stood between Ó'hAilpín and a premiership season match.
"I remember Jim Stynes when he first came across, it took him a couple of years, and it might still take Setanta that time to really establish himself," Pagan said. "But I know he is going to do it. He is just a unique young man. He has a real desire and hunger that you don't see a hell of a lot.
"He has been a real plus for our club. The enthusiasm and keenness, he is very popular with his team-mates and he just wants to get better."