Leinster have to got to 'breakdown' Munster
O'Mahony and Varley back
Leinster v Munster, Aviva Stadium, Today (KO 6.30), Live Sky Sports 2.
It looks like Leinster are gearing up for what Seán O'Brien likes to call a "man-up-athon".
Coach Matt O'Connor makes three changes from last week, all in the forward pack. Props Jack McGrath, in for Cian Healy, and Mike Ross add weight to the scrum.
There is what can best be described as a horses-for-courses swap in the second row with Ireland's Mike McCarthy joining Devin Toner in the engine room with Australia's Kane Douglas set for an impact role.
There is a needs-must approach to Leinster's set-up at ten, twelve and thirteen, otherwise known as Jimmy Gopperth, Ian Madigan and Gordon D'Arcy given how Zane Kirchner failed to beat the injury clock.
This three give Leinster a wide variation in passing, kicking and running options with D'Arcy's security in defence and greater space to use footwork in attack a real benefit.
The breakdown is always an area of hot debate when this fixture comes around.
Leinster have captain Jamie Heaslip, Dominic Ryan and Rhys Ruddock manning the back row jerseys.
They will have to be on the ball quickly to prevent a fast roll-out from Conor Murray to Ian Keatley and two big carrying centres in Denis Hurley and Australian Andrew Smith.
The hammer blow announcements that Leinster have lost Healy and Sean O'Brien long-term has been followed by the confirmation Peter O'Mahony and Damien Varley are back for Munster.
But, both of them will begin the evening on the bench.
They are not the only strong men held back as BJ Botha, Dave Kilcoyne provide worthy options up front and JJ Hanrahan and Gerhard van den Heever the speed of thought and movement.
Munster coach Anthony Foley changes more than half the team - eight to be exact - that suffered so badly against The Ospreys at Thomond Park last week.
The return of O'Mahony from a double shoulder procedure is incalculable to the Munster cause.
He will enter the fray for the first time since the Heineken Cup quarter-final against Toulouse in April.
The involvement of Varley should not be under-estimated as he makes his first appearance of the season. He is a beast on the floor and a hard-man right at the heart of their pack of forwards.
However, the mere fact O'Mahony and Varley are kept in reserve is a compliment to the confidence in which Foley holds the back row of CJ Stander, Tommy O'Donnell and Robin Copeland as well as novice hooker Duncan Casey.
There are also Leinster old boys to add to the cocktail with Copeland, Keatley, wing Andrew Conway and full-back Felix Jones, their captain, all set for a rousing reception.
Not to mention Leinster's men from Munster Eoin Reddan, Sean Cronin and Mike Ross.
Leinster: R Kearney; F McFadden, G D'Arcy, I Madigan, D Fanning; J Gopperth, E Reddan; J McGrath, S Cronin, M Ross, D Toner, M McCarthy, R Ruddock, D Ryan, J Heaslip (capt).
Munster: F Jones (capt); A Conway, A Smith, D Hurley, S Zebo; I Keatley, C Murray; J Cronin, D Casey, S Archer, D Foley, P O'Connell, CJ Stander, T O'Donnell, R Copeland.