Ireland forwards coach Simon Easterby said Kilcoyne, 29, had joined the rain-hit training session but was not an official member of the tour squad.

The assumption, however, is that Kilcoyne’s arrival in camp is not unconnected to Healy’s issue with an AC joint sustained in the 46th minute of the series-levelling second Test victory in Melbourne, despite a positive injury update after training.

“We had a couple of guys who were managed today but on the whole, I believe the players have come through,” Easterby said.

“They've recovered really well, the medical staff and conditioning staff have done a great job getting the players right and the players themselves have really looked after themselves after a pretty bruising encounter in Melbourne.

We were delighted with the numbers that were able to train today.

Healy, flanker Dan Leavy (sternum) and wing Andrew Conway (hip) all picked up knocks during the 26-21 win over the Wallabies at AAMI Park, which sends the teams into a series-deciding final Test at a sold-out Allianz Park this Saturday.

“Cian trained, Dan we managed a bit but he did some stuff. Andrew is still carrying quite a nasty hip pointer but the way they've presented themselves 48 hours post-game is very encouraging.

“We're pretty happy with the availability of training today but also the way the players have shown up today and even the guys that have carried some serious bumps from the weekend are looking far better than expected.

Asked whether any players had been added to the squad, Easterby replied: “Not to the official squad, no, no one's come in.”

Yet when asked specifically about Kilcoyne, who had been photographed in Ireland training kit with the squad during the session, the forwards coach replied: “He has been in for just today. He's not been made officially part of the squad.

“He was travelling.

He's not been officially named in the touring party, but he is available as he's Irish-qualified.

Kilcoyne is not the first unannounced player to train with Joe Schmidt’s squad on this three-week tour.

Sale Sharks’ Irish-qualified utility back Will Addison spent time with the Grand Slam winners in Melbourne last week ahead of his summer move to Ulster.

“Certainly, in Will's case, he was over visiting family and he had an opportunity to come in and I guess when you've got someone who's moving to Ulster and is Irish-qualified and we had the opportunity to get him into the squad was good, and for the players to meet him. It was quite a useful time for him and for us to see him in action.”

While Easterby insisted no-one had been ruled out of selection for the final game of the season “yet” the assistant coach added: “I think there will be some changes, whether that's the starting team or the bench.

“There's always going to be an opportunity through a three-Test series, not only through injury but also through our need to try and get some exposure for some of the more inexperienced players on a tour like this.

We're not that far out from a World Cup and this has been a great tour for us to get to know players who we're maybe not that familiar with and get some game time and training time with those players.