There has been a shadow cast over the fitness of Rob Kearney ahead of Ireland's Six Nations tussle with Italy this Saturday .
The automatic first choice full-back has been dogged by a hamstring-back injury that resurfaced again yesterday, immediately opening up a debate on who will possibly fill the shirt.
The concern over Kearney's injury might stretch beyond the Six Nations.
"It's kind of like having kids, you always worry about them," said Greg Feek, Ireland's scrum coach.
"You always worry about your backs, you know what I mean? That never stops.
"But, I don't want to throw out random comments about Rob (Kearney) himself.
"Hopefully, we'll find out exactly what's going on, on Thursday with him."
The fact of the matter is Kearney has played two sets of 80 minutes against France and England and six matches for Leinster since the World Cup.
The recurrence of this injury almost certainly rules the Leinster full-back out given how coach Joe Schmidt always likes to have his game-plan and his first 15 bedded in early in the week.
There are three options.
Simon Zebo started at full-back against Wales. Jared Payne is fully fit and a natural there. Robbie Henshaw has often played there for Connacht.
The withdrawal of Payne to what is arguably his best position would be a huge vote of confidence for the long-term future of the midfield axis of Stuart McCloskey and Henshaw.
The retention of Zebo would allow Schmidt to reunite Henshaw and Payne.
The move of Henshaw would make for an all-Ulster McCloskey-Payne combination.
There are the immediate concerns for Kearney's injury and the calf problem that makes scrum-half Eoin Reddan a doubt with Kieran Marmion ready to back-up Conor Murray.
Flanker Tommy O'Donnell took a full part in training to relaunch his bid for the back row.
Then, there are the long-term considerations such as the concentration on two tight-head props in Mike Ross and Nathan White, who are 36 and 34 years old, respectively.
"It would be (a worry) if they were running around like that," said Feek, in defence of his men. These days, the age factor's one thing but performance is the other.
"These two have been together since the World Cup. We've invested in them for this season. Other guys have been in with us, had a look; obviously Marty's out injured."
The injury to Marty Moore has been compounded by bringing Finlay Bealham in as cover for both sides when Tadhg Furlong, now deposed, filled that brief at the World Cup.
Twenty-three year-old Furlong will be back.
"It does take three years or so to develop someone," said Feek.
"During those three years you have ups and downs and little critiques here and there and then it's just a matter of letting them go and then learning while they do it.
"One day you can think there's not much coming through, then you can wake up in the morning and there's a whole lot ready to go."
The frustration Ireland feel about the way the referees managed the scrum battles against Wales and France could resurface against the Italians on Saturday.
"I think there's been a slight change since mid-way through the World Cup that I've noticed in terms of what's been policed consistency.
"It's a big learning (curve) for all of us, for me, in particular, and for the players.
"To coach to the letter of the law and for the players to be able to do it is probably a lot harder than just saying 'go for it'.
"I have seen a change since the start of the Six Nations which is a little bit frustrating, but you've got to live with it."
There is also the vexed question over player safety gnawing away at Feek as adapting to the referee's interpretation often means counter-cheating the cheat.
"It's a safety issue. That is the responsibility for us," he said. "If you are saying to a guy look I want you to dive in on an angle at the ground at 100 miles an hour, that is irresponsible."