It is the question that will not go away as long as it is not answered.
There is understandable interest in where Joey Carbery's long-term future will be.
The presumption from early this season was that he would make his way to out-half after a suitable period of transition into professional rugby.
A meteoric rise has seen Carbery move from Man of the Match for Clontarf in the All-Ireland League final at The Aviva Stadium last May to the same accolade in the Champions Cup quarter-final back in the same stadium last week.
"Joey's growth over the last while has been phenomenal," said Leinster backs coach Girvan Dempsey.
"He is learning fifteen and you can see the progression he's made over the last while.
"He has that versatility that we see him playing at ten as well."
It is a story reminiscent of Ian Madigan, the alternation between ten and twelve hindering his stated ambition to take full control at out-half.
It was an important factor in Madigan's decision to make the ill-fated move to Bordeaux -Begles.
Jonathan Sexton and Rob Kearney are going nowhere, as long as their bodies hold up to the challenge.
The difference at full-back is that Carbery has given Leinster a different dimension on counter-attack and a different problem to solve by moving into first receiver.
Just as important as Carbery's talent is his mental inclination to leave mistakes behind him.
It showed in how he was twice in trouble when isolated and taken down by Wasps, the first on the end of Joe Simpson's tackle prompting a turnover for Christian Wade's try.
"You can see he's not effected by anything that happens," said Dempsey. "He is just able to park a good or bad moment in the game and move on."
Former full-back Dempsey, Kearney and Isa Nacewa have been there for Carbery," said Dempsey.
"A lot of people contribute to everyone's growth.
"I've sat down with him and Rob has sat down with him to have a discussion on a few things.
"It is just trying to impart knowledge and help him see things in a different way."