Fans will have belief that management can pick right squad to get the job done
Whatever way it's spun, there is no denying last week's loss to Treviso was a bad day in the home office.
It is very easy to dismiss it as a one-off slip up, however, if Leinster struggle against the Scarlets, the lamenting minds will revert back to this sobering defeat.
There were fundamental mistakes throughout the game, and for an experienced side like Leinster, worryingly, at no stage did they have control, and furthermore had no answer or catalyst to stem change.
This, of course, is no reflection on a Treviso side that took their chances well but the Aviva Stadium and the RDS have been fortresses for Leinster and have struck fear into travelling sides in recent years, but not the Italians last weekend, and the same logic applies to Scarlets tomorrow.
The problem with losses like this is that it widens the gap between the front line squad and back benchers.
In recent times, between injuries and performances that seemingly never ending talent pool has become very shallow.
Depending on availability, the management will be under no illusion this weekend as to the 23 players they will want out on the pitch.
The week before the biggest game of their season, Leinster had their worst performance of the campaign at home. That is far from ideal.
Two crucial factors contributed to this vital loss: the selection of Jack McGrath as captain should not have happened, not because he is not up to it but when you have one of the best front-rows in the world just let him play.
His experience in the side alone will give leadership, so just leave the direction to someone else, preferably someone who hasn't got their head in the coal face.
Secondly, Joey Carbery has not been the same player he was pre the Autumn international with Fiji. Whether he has not recovered from his injury in that game, or confidence is low, is debatable, but the level of expectation on his shoulders was not matched by his performance.
There will be those who say he has not had game time but in my opinion 80 minutes against one of the worst teams in the PRO14 at home should have allowed his quality to shine through. The management need to find out why this didn't happen.
It doesn't help when the lineouts and set-pieces were malfunctioning and, as the slow-motion car crash continued, it was up to the bench to steady the ship and get some control in the game .
Luckily enough, Scarlets weren't much better last week, but they will relish their chances and understand that Leinster are probably more vulnerable now than they even were last season.
Back then, Leinster were in better shape physically but not as experienced. This year, it is the opposite. Still, the foundation work achieved this season will see Leinster through.
They have had a clean sweep in their pool games, beaten some of Europe's major brand names, and since the last World Cup, have had a constant supply of new talent emerging through the system.
That talent has emerged as front liners like Dan Leavy, James Ryan and Tadhg Furlong are now some of the first names on the team sheet.
Where the decisions need to be made this week are on the injury front. There are a lot of players almost game ready but may not be.
All of these players are game changers with vast experience so making the right call on their progress would have been the priority for the management this week.
Leinster have come a long way this season and are well capable of league and cup honours. However, we have been down this road before.
Scarlets are coming over believing they can spoil the expected party. They have taken some impressive scalps this season including Bath and Toulon, and last year both Leinster and Munster.
The belief will be with Leinster tomorrow but it will not be an easy ride for supporters or players.
The time toiling over the personnel both available and to be selected will have been felt by both management and fans. But the belief will be that the 23 selected will be good enough to progress to the final.