For some of the world’s most revered front row players, it is the ideal situation. For the coaches it lies somewhere between walking on eggshells and urging the turkey to deliberate over the seating plan for Christmas dinner. We are talking about these brutes being the only choice in their position.

It’s not the first-choice front-rower’s fault. Having worked hard over an entire career to be the standout in one role, it must be the dream to be the irrefutable selection. After all, reputations for props and hookers can be stained on; impossible to remove and often talked about, regardless of performance.

However, for a certain few Test coaches, as we head into the Rugby World Cup, any comfort in certainty of selection must be offset by a sense of foreboding as that one nailed-on front row risks doom with every minute more they play.

Okay, you cannot go into games with fear. But with Joe Schmidt, Heyneke Meyer, Steve Hansen, Vern Cotter, and Warren Gatland there may well be a quickening of the pulse whenever they stay on the ground for that extra second to catch their breath.

Take the example of Mike Ross with Ireland. The tighthead is undeniably Ireland’s front-line No 3 and while he keeps starting warm-up games, the auditions for his back-up continue from the bench. Martin Moore has considerable talent, but could the sky fall in if Ross were to injure himself on the eve of the World Cup? With France and Italy as scrums in waiting it would certainly be a concern.

On hand: Mike Ross in Six Nations action for Ireland

On hand: Mike Ross in Six Nations action for Ireland

As for New Zealand, they’ve painted themselves into a corner with their choices at loosehead. Wyatt Crockett is 32 years old, but is the perennial substitute, such is the over-reliance on Tony Woodcock, only two years his senior. The former has just crested 40 caps, with over half from the pine, while the latter has hit 115 since 2002.

Woodcock has faded in recent years, noticeably becoming less of a menace at the head of the scrum. However, he offers more to a squad. He is a trusted lieutenant for Hansen and Richie McCaw, allowed a little slack thanks to his experience, and he is as straight talking as a grizzled veteran can be. After all, this is a man who allegedly stood up after an impassioned speech from John Kirwan during the darkest days of the Blues reign of errors a few seasons back, as the coach pleaded with his underperforming players to show more love for each other, and proclaimed: “We’re just a bit f****** s***, lads!”

Well back: The whole nation seems to be behind Samson Lee, hoping he recovers

Well backed: The whole nation seems to be behind Samson Lee, hoping he recovers

There are other players out there that would be unimaginable omissions from the scrum. Whatever you make of his lineout work, Scotland packing down without Ross Ford sounds odd now. South Africa without the trio of Tendai Mtawarira, Bismarck du Plessis and brother Jannie sounds just as crazy, though Bismarck is not totally assured – a blessing, with his often on-edge play. As for Wales worrying about the health of Samson Lee… well, despite a long lay-off and only 12 Test appearances, he has shown Gatland enough to merit pushing ahead of other young props. He’s simply so important – to the extent where the whole nations is eagerly awaiting any fitness updates – but he is considered “touch and go” for this tournament.

We cannot urge against picking and sticking now – we’re a few years too late to uncover quality, like-for-like replacements for the irreplaceable. This is how it is. All we can do is wish the incumbents all the best and pray they stay fit.