Eighty percent of Andy Farrell's Irish squad for the 2023 Rugby World Cup is as good as set in stone, but there are still places on the outskirts that hang in the balance.
From a provincial stand point, the focus of the URC quarter-finals will on the goals of the collective 23s, which is to make the semis, but there are a group of individual who have more selfish reasons to play well and to look good.
We have taken a look at who these players are, and what these matches mean for them in the context of World Cup squad places.
With Joey Carbery once again left out of the Munster 23, his chances of making the World Cup squad have taken another hit.
Should Munster lose tomorrow, his final opportunity to impress will be in the World Cup warm-up games, and even then his participation is far from guaranteed.
Should Munster win, they will be sticking with the Crowley/Healy combo for the next round.
The odds are firmly stacked against him, and it is looking increasingly likely that the third out-half spot will go to one of Jack Crowley, Harry Byrne, or possibly Ciarán Frawley.
Crowley is somewhat fortunate to be starting against Glasgow, given that he has been outshone by Ben Healy in Munster's recent South African outings.
He is still the most likely to travel to France as third choice 10, but an assured performance tomorrow, without the need for a Healy rescue job, is of upmost importance.
Harry Byrne is slowly clawing back trust with the rugby public and the Irish selectors, after a run of injuries and a loss of form.
It cannot be understated how big an opportunity tomorrow is and how crucial his level of performance is in the context of the World Cup squad.
Should he produce the required goods against the Sharks and in the semis, he just might keep the reins for a potential final.
Should he fail, Crowley's claim grows ever stronger.
Frawley starting at centre will arguably increase his chances of a World Cup call up. A strong showing adds to the argument for bringing three centres and a utility number 10.
Loose Head Prop
The third choice World Cup loosey is another intriguing race, featuring three men with different qualities and different levels of experience.
Loughman's injury, which kept him out of Six Nations contention, looked like it could have had devastating consequences for his World Cup chances.
However, he came back just in time for Munster's South African venture, and their upturn in form and fortunes.
His performances - lining up well against Frans Malherbe and Thomas du Toit - looked even better when juxtaposed to Munster's front five outings against Glasgow and the previous Sharks game.
Dave Kilcoyne's fall from the Munster 23 has been overshadowed by that of Joey Carbery's, but may be just as significant.
He does have, however, what could the most valuable asset of all: substantial international experience.
Michael Milne is third in line having been called up to the Ireland squad during the Six Nations, but, like Harry Byrne, a strong URC run-in could lead to WC warm up game time and a trip to France in September.
His ball carrying is a superb asset and sets him apart from the two Munster options.
A few questions surround the back row selection for the World Cup; will a scrum-half or centre be dropped to leave space for sixth back rower? Will Baird be listed in the second row or as a flanker?
These questions won't be answered until the squad is announced, but certain players can affect the chances of potential outcomes.
Having said that, it is arguable that Gavin Coombes' performance tomorrow will not have a bearing on his World Cup hopes.
He has been extremely dominant and at times unplayable for Munster over the past three seasons. Yet, he has not been rewarded with the international opportunities.
What more can he do? Despite his form, he has failed to convince the jury of Irish selectors, beyond all reasonable doubt, that he is in fact good enough.
Should five back rowers be brought, his ball-handling and ball-carrying skills may be deemed as surplus to requirements given the presence of Caelan Doris and Jack Conan.
Cian Prendergast appears to be a strong bet to travel, and if he continues his form this evening in the 'unfamiliar' position of number eight, the show of versatility will be of huge benefit to his cause.
The Connacht man and Nick Timoney are the only two mentioned in this article who will be lining out against each other this weekend, adding another layer of importance and interest to their battle at Ravenhill this evening, and allowing us to see more clearly whom the better option may be.
Timoney has fallen back since November, when he was winning the race over Prendergast and Coombes, and now has the chance to make up serious ground.
It is hard to envision Scott Penny on a plane to France, given his lack of international experience and the weight which that particular asset holds in the eyes of the selectors.
But, a promising URC run could lead to better things.
Jordan Larmour's error ridden performance against Toulouse stood out in the midst of the many superb showings at the Aviva last Saturday, and he will be looking to right that wrong against the Sharks.
Robert Baloucoune's star has fallen as well since starting against South Africa and Fiji in November, and his lack of versatility will count against him.
Still, his pace is unmatched among the other options, and if he can get ball against Connacht and in upcoming rounds, a ticket to the World Cup warm-ups may be within his grasp.
The absence of Andrew Conway and Keith Earls adds further dilemma to the back three situation, but both men have enormous amounts of good will in the bank with Andy Farrell and Ireland.
However, this does provide an outside chance to the two Munster wingers, and in particular Calvin Nash.