While Joe Schmidt and Warren Gatland have done their best to soothe concerns about Brian O'Driscoll's fitness, the fact that the most celebrated tourist of the 21st century could not even board a plane to London for yesterday's first official Lions gathering must raise eyebrows.
As those of us with occasional back spasms – and much less celebrated sporting careers – can verify, the affliction is certainly capable of flooring even the most ferocious of warriors.
However, despite his public protestations, Gatland cannot but have viewed the scene at the RDS last Saturday of his only truly established world-class centre collapsing to the ground, before resuming his stance, then faltering once more like a fledgling lamb, with anything but the gravest of concern.
That Gatland confirmed his intimate knowledge with this as a regular back spasm problem that can happen at any time only heightens the fears surrounding O'Driscoll's fitness as he steps up for his quest for a twin trophy haul with Leinster later this month and, beyond, a Lions tour.
Adding Eanna Falvey, the Irish team's medical doctor, to the Lions roster may ultimately prove to be one of Gatland's canniest additions to the back-room staff, given how well he knows the workings of the O'Driscoll body.
For if O'Driscoll is finding it difficult to last a short hop from Dublin to London, the arduous nature of the long-haul trek to the southern hemisphere, in addition to training commitments, indicates that the 34-year-old will need to have his fitness monitored closely.
"Brian has been told to stay off his feet for 48 hours and this back problem is something that comes and goes," revealed Gatland yesterday. "It normally takes just a few days to relieve the pain. We will keep our fingers crossed he is able to play in the two Leinster games that are coming up.
"The information has just been to keep him off his feet for 48 hours and it is something that he has had that tends to come once a year at some stage, it is normally just the case of an epidural at some stage.
"We have known in the past he has had problems with his back and that it has gone into spasms during a game."
Schmidt also confirmed yesterday morning that the next 24 hours or so would be crucial in determining the preparedness of one of the Lions linchpins as his Leinster side prepare for a gruelling double finals date against Stade Francais and Ulster.
"I wouldn't be overly concerned," said Schmidt. "His back tightened up and he felt he couldn't really stretch out. He was keen to continue, but it just wasn't an option."
Such is O'Driscoll's remorseless spirit, his willingness to battle beyond the pain barrier is at once his greatest asset and a liability; Gatland is on record as confirming that he will not gamble with the fitness of any player, even his most decorated squad member. In the light of O'Driscoll's scare, Gatland was moved to reveal his fears about the mountain of work still to be undertaken by Leicester, Northampton, Ulster and Leinster players over the next fortnight.
"Ironically, those players not in the finals will be in a better position in terms of preparation for the tour and it does put the other guys at a bit of a disadvantage," he stressed. "We are preparing for the fact a couple of players may pick up injuries that affect their ability to tour."
Gatland's revelation that there is a standby list of some 40 players, after previously refusing to divulge if this was the case, reminds us that injuries are a part and parcel of the build-up to Lions tours.
Since the 1993 tour, an average of five players have had to be called up to the party because of injury before or during the Test series and Irish players have suffered in this way before.
Four years ago, Munster scrum-half Tomas O'Leary crumbled to the turf in agony against Llanelli Scarlets, a broken ankle confirming his tour was over just days after absorbing the joy of being included in Ian McGeechan's squad.
And although Stephen Ferris boarded the plane in the best condition of his career and, at 23, was arguably Europe's most explosive forward and an automatic selection for the first Test, backboned by try-scoring outings against the Golden Lions and Free State, he succumbed to a training-ground injury before a ball had been kicked in the Test series.
Poor Jerry Flannery didn't make it that far, damaging elbow ligaments in England's Pennyhill Park in another freak training-ground accident.
In 2005, Malcolm O'Kelly was ruled out when a groin injury deteriorated sufficiently for him to be supplanted by Simon Shaw in Clive Woodward's over-populated travelling party to New Zealand.
Ironically, there were no major injury scares the last time the Lions toured Australia, in 2001, yet there were the most call-ups in modern history. Among the seven fortunate to get the call were Irish duo Tyrone Howe and David Wallace.
In 1997, while everyone recalls Paul Wallace's destruction of the Boks, the Saracens prop wasn't initially named in the squad.
Instead, it was his fellow Irishman Peter Clohessy who was selected but the more experienced front-rower had to pull out with a back injury on the first day of their pre-tour training camp and just a week before departure.