Ulster, after their win last night, are eight points adrift as will Leinster be if they win this evening. And Munster have two trips to Wales before their final game here against Connacht.
So there's a long way to go yet before the semi-finalists are decided but things will be a lot clearer come nine o'clock tonight.
Tony McGahan runs with a bold selection, young Conor Murray at scrum-half ahead of Peter Stringer, Felix Jones at full back in place of Paul Warwick and Donnacha Ryan at blindside with Denis Leamy on the bench.
But all hace impressed in recent games and there is the feeling that McGahan's faith may find its reward.
Leinster supporters, - supporters mind, not the players - will trickle into Limerick with 'Six in the Sticks' tripping from their tongues, gladly trotting out the undeniable recent record but there has never been much separating two fine sides in recent times. In the last three games there was just one try scored, that by Leinster who of course went on to win.
Tonight though, it will be decided by a series of Ifs and What Ifs.
First off however, forget the, What if Leinster have one eye on next weekend's European quarter final - They don't.
But if Munster gain parity up front and their set piece continues to improve as it has over the last number of games then contrary to opinion inside the Pale, Munster have the wherewithal in the backs to make it count.
And when Leinster are in possession, if Munster can curtail the threat posed by Isa Nacewa and the mercurial Brian O'Driscoll, then it'll be easier to close the deal.
But here's an If you can bank on.
If both sides bring their best game to Thomond Park Stadium this evening, those fortunate enough to be there, will witness as good a game of rugby as has been seen all season (the Canterbury Sharks Twickenham Super 15 excepted).
Until maybe these sides meet again in the knock-out stages ?
Munster: F Jones; D Howlett, J Murphy, L Mafi, K Earls; R O'Gara, C Murray; W du Preez, D Varley, T Buckley; D O'Callaghan, P O'Connell (capt); D Ryan, D Wallace, J Coughlan. Replacements: M Sherry, M Horan, J Hayes, M O'Driscoll, D Leamy, P Stringer, P Warwick, S Tuitupou.
Leinster: I Nacewa; S Horgan, B O'Driscoll, G D'Arcy, L Fitzgerald; J Sexton, I Boss; C Healy, R Strauss, M Ross; L Cullen (capt), N Hines; K McLaughlin, S O'Brien, J Heaslip. Replacements: A Dundon, H van der Merwe, S Wright, D Toner, R Ruddock, E Reddan, I Madigan, F McFadden.
Referee: A Small (England).