Cold hard facts. Leo Cullen makes the natural leap from player to coach next summer while Brian O'Driscoll retires.
All that can be done is to soften these blows.
Factor in the clear and present danger of Jamie Heaslip joining Toulon and Matt O'Connor could well be viewing tonight's tussle with Ulster as auditions for those who must try to fill these deep, dark voids. And so, with Leinster soon to lose two, possibly three, heroic figures, games like this evening matter.
At least the progress at lock is well under way with Devin Toner and Mike McCarthy all but established as the starting European partnership. Cullen, of course, will dispute that to the death.
One from Tom Denton and Quinn Roux may also come good.
Outside centre initially went to Lote Tuqiri when O'Driscoll was injured but the cross-code veteran is back in Australia, opening a slot for Brendan Macken.
Tonight's partnership with Noel Reid is just the second time the St Michael's/Blackrock graduates make up a senior Leinster midfield. The other occasion being a 21-20 victory in Treviso on November 24th.
“They haven’t played that much together but historically they have and both bring each other into the game quite well,” said O’Connor. “Their styles complement each other,”
Adolescent rivalry
O'Connor is making reference to the pair's adolescent rivalry before they became teammates at representative level. Reid is almost exactly a year older.
Tonight feels important for them as Luke Marshall and Darren Cave will be ultra-keen to obliterate potential threats to their international careers further down the tracks.
“Against Marshall and Cave it will be tough ask for them but I’m sure they are good enough,” said O’Connor.
The real conundrum facing Leinster is in the backrow, number eight in particular.
It's that bottle neck problem again. Jordi Murphy, still only 22, is looking more like Test-standard on each viewing. Injury slowed his rise somewhat but with Montpellier and Toulon showing genuine interest in Heaslip, while the IRFU are yet to offer a deal to keep him in Dublin, Leinster's possible loss this summer would be Murphy's gain.
Starting trio
O'Connor likes pretty much everything about Murphy and tonight's backrow – along with Rhys Ruddock and O'Brien – may well be Leinster's starting trio in the future.
“Jordi carries the ball very well for us. He has a very broad skill set so he can play across the backrow.
“That said, last year and early this season, whenever Jamie wasn’t around, he probably filled that eight shirt best,” said O’Connor.
That leaves Kevin McLaughlin pursuing Ruddock with Shane Jennings and Dominic Ryan keeping O'Brien honest in the seven jersey. O'Brien the Number Eight cannot be discounted either. Or O'Brien the blindside flanker.
One concern about the Tullow farmer is his durability if thrust into the hectic Top 14 game-on-game routine.
Granted, he recovered from a serious hip operation last season to eventually excel for the Lions in Australia. However, that tour and further injury has curtailed his involvement this term to just seven games – four with Leinster and three with Ireland.
Ireland coach Joe Schmidt clearly agrees with the value of putting O'Brien out to wrestle with Sydney-born Irish man Sean Doyle tonight.
Run out number eight then. That should have O'Brien ideally tuned come the Six Nations.
O’Connor concurs: “The thinking is we would like to give him a bit more rugby.”
Not too much of course. Just enough.
