Comment: Why sidelined Rory Best has reason to fear for Ireland captaincy
Australia v Ireland, First Test, Suncorp Stadium, Saturday, 11.00am
This month, Rory Best will face an unusual and potentially uncomfortable experience as he watches his team play in Australia without him.
As he does, he will wonder whether it will be his team when they come back.
Since the 2015 Rugby World Cup, Ireland have played 28 games and Best has captained the side in 22 of them.
Three of the games missed came last summer when he was away with the Lions, while Joe Schmidt rested him for the wins over Canada in 2016 and Fiji a year later.
The only match of real consequence he was forced to sit out was the Six Nations win over Italy in Rome last year when he suffered a stomach bug on the eve of the game.
He has led his team to history in Chicago and Cape Town, and captained them to a Grand Slam, but the lingering doubt surrounding his captaincy has centred on his age and his capacity to lead the team to Japan next year when he will be 37.
Often we are too quick to rush players into early retirement, but as he maps out his 2019 vision, Schmidt must wonder how long the Ulsterman can continue to operate at the very highest level.
Already there are signs that he is slowing down.
Although he was available for every Test match, he has been beset by injuries and started just seven games for Ulster this season.
He was prominent during the final showdown in Twickenham, but in the other Six Nations games he was probably Ireland's least influential forward.
After lifting the trophy on that freezing evening in London, Best sat alongside his coach at the post-match press conference when Schmidt was asked: "How much would you like to see your Grand Slam skipper stay on and skipper Ireland through to the next World Cup?"
At the time, his contract had been agreed but was yet to be announced, but the head coach was evasive as he slowly and deliberately delivered his answer.
"He's getting faster and faster on that zimmer frame," Schmidt said.
"That's something that could come to fruition hopefully sooner rather than later, but it's like everything. Rory, it's hard to get him to make a decision, but we'll see how we go with that."
However, there has never been any indication that the captaincy was up for debate and, when the squad was announced a week ago, the letter 'C' was inked in beside Best's name as usual.
He attended the eve of departure function at the Australian embassy and spoke about the series on stage with Schmidt and Wallaby legend Michael Lynagh. The first word that Best was out came from Schmidt, who casually dropped the news into an answer to a question about the big news of the day; Joey Carbery's move from Leinster to Munster.
Although he has yet to finalise his plan for the captaincy, it appears to be to proceed with Peter O'Mahony and Johnny Sexton as the co-leaders of the squad Down Under.
Throughout the Six Nations, it was noticeable that the duo were becoming more prominent as the tournament went on.
O'Mahony, who has long been considered next in line and captained Ireland on tour in North America in 2013, has been Munster skipper for six years and led the Lions in their first Test last summer.
Sexton has been a leader in this team for as long as he has been in it, but concerns about his manner with referees and the potential distraction of dealing with the media in the build-up to big games have faded.
Indeed, he appears to be relishing the role.
Best has been hailed for his calm presence as a leading light, but with such high-calibre lieutenants ready to step into the breach it is hard to see Ireland suffering a leadership deficit in the coming weeks.
Will they miss him in his primary role as starting hooker?
Certainly, the experience of 111 caps is not to be sniffed at, but Ireland are up against an Australian side who lost their only capped hooker, Jordan Uelese, and will have two uncapped options, Folau Fainga'a and Brandon Paenga-Amosa, to select from this week.
Sean Cronin appears to be in pole position to profit from Best's absence and, while he has only started nine of them, he can hardly be called inexperienced having won 61 caps for his country.
He has proven for Leinster that he can be a consistent performer as a starter.
He's been the stand-out hooker in Irish rugby this season playing alongside Cian Healy and Tadhg Furlong in the Leinster front-row. He fully deserves the chance to start on Saturday.
Before departing for Australia, Schmidt said Cronin, Rob Herring and Niall Scannell are playing for the chance to be the back-up hooker next season, but one suspects that three strong performances against such quality opposition means the jersey will have to be won back come November Internationals time.
No doubt Ulsterman Best, who has signed a national contract through to the World Cup in Japan next year, has no intention of giving up his position without a fight - but this would appear to be a costly tour indeed for the captain to miss.