Connacht head coach Pat Lam has made three changes to his team to face the Ospreys as he continues to come to terms with an injury crisis.
The Westerners have over 20 players who are either on the injury list or being rested and this week Lam revealed that he had tried to draft in his son Mitch to fill a gap, only to be blocked by the IRFU.
With Kieran Marmion rested this week, scrum half John Cooney makes a timely return from injury to start in a backline that's otherwise unchanged from the New Year's Eve defeat to Munster.
Up front, the back row is changed with the introduction of Sean O’Brien at blindside flanker and Naulia Dawai at Number 8 for his first Connacht start.
Tom McCartney will captain the side in the absence of John Muldoon who had, up to now, started every game this season but was ruled out this week with a hamstring injury.
From the bench, Galway man Eoin McKeon is in line to make his 100thConnacht appearance if he is called upon in Wales tomorrow afternoon.
Connacht: Tiernan O’Halloran, Niyi Adeolokun, Rory Parata, Peter Robb, Matt Healy, Jack Carty, John Cooney, Denis Buckley, Tom McCartney, Finlay Bealham, Quinn Roux, James Cannon, Sean O’Brien, Jake Heenan, Naulia Dawai
Replacements: Dave Heffernan, JP Cooney, John Andress, Lewis Stevenson, Eoin McKeon, Caolin Blade, Danie Poolman, Ciaran Gaffney
Johnny Sexton will make his Leinster return in Friday's Pro12 clash with Zebre at the RDS.
The out-half hasn't played since sustaining an injury to his hamstring in the Autumn International against New Zealand on 19 November.
He will captain the side at number 10, partnering Luke McGrath who continues at scrum-half.
In all, there are seven changes to the side Leo Cullen sent out against Ulster on New Year's Eve.
In the backs, three internationals return with Zane Kirchner taking up his place at full-back, as Adam Byrne and Rory O'Loughlin continue on the wings.
The second change sees Robbie Henshaw come in to the number 13 jersey to partner Garry Ringrose in the centre.
In the pack, Cian Healy and James Tracy start alongside Michael Bent who will win his 75th cap for the province.
Devin Toner and Hayden Triggs are again selected as the second-row combination but there are two final additions in the back row.
Dan Leavy starts at blindside flanker, with Jack Conan coming in at the base of the scrum in the number eight jersey.
Sean O'Brien starts again this week but with Leavy starting at six, O'Brien swaps across and fills the number seven jersey for the final Pro12 game before attention turns to the Champions Cup.
Leinster: Z Kirchner; A Byrne , G Ringrose, R Henshaw, R O'Loughlin, J Sexton (capt), L McGrath, C Healy, J Treacy, M Bent, D Toner, H Triggs, D Leavy, S O'Brien, J Conan.
Replacements: S Cronin, J McGrath, T Furlong, R Ruddock, J Heaslip, J Gibson-Park, R Byrne, N Reid
The Ulster team to face Scarlets in the Guinness Pro12 on Friday evening features nine personnel changes from the one which lost out to Leinster at the RDS last week.
Ireland captain Rory Best returns to the line-up for the match in Llanelli, as do fellow internationals Iain Henderson, Paddy Jackson and Luke Marshall.
Best will be joined in an all-new front row by props Callum Black and Ross Kane, who will make his second senior start.
Henderson will partner Kieran Treadwell in the second row, while Chris Henry is elevated from the bench to start in the back row alongside Clive Ross and Sean Reidy, who switches to number eight.
Louis Ludik and Jacob Stockdale come into the back three, where they are joined by captain Andrew Trimble.
Marshall and Stuart McCloskey will line up in midfield, with Paul Marshall and Jackson occupying the half-back positions.
Named among the replacements, Jonny Simpson will be hoping to earn his second cap after impressing off the bench last week against Leinster. John Andrew, Andy Warwick, Franco van der Merwe and Pete Browne will provide additional forward cover.
Elsewhere, Dave Shanahan could make his first senior appearance of the season if called upon. Brett Herron and Tommy Bowe complete the match-day squad.
Scarlets are one of the competition's in-form teams, having been defeated just once in the last nine rounds of Pro12 action.
Ulster: L Ludik, A Trimble (captain), L Marshall, S McCloskey, J Stockdale, P Jackson, P Marshall; C Black, R Best, R Kane, K Treadwell, I Henderson, C Ross, C Henry, S Reidy
Replacements: J Andrew, A Warwick, J Simpson, F van der Merwe, P Browne, D Shanahan, B Herron, T Bowe
