Rónan Kelleher will captain Leinster for the first time, as head coach Leo Cullen makes nine changes to his side for Saturday's trip to Scarlets (live on RTE2 and RTÉ Player).
The Leinster coach has kept almost all of his first team regulars on ice for next week's Champions Cup semi-final against Northampton, although Kelleher, Ryan Baird, Jamie Osborne and Ciarán Frawley do start in a largely youthful squad.
Jamie Osborne moves from full-back to centre this week, where he joins Liam Turner, while Jimmy O'Brien continues on the left wing, with Andrew Osborne starting on the right.
Fintan Gunne comes in for Luke McGrath at scrum-half, partnering Ross Byrne, while Frawley moves to full-back.
Cian Healy comes in at loosehead, joining Kelleher and Thomas Clarkson in an international front row, while Brian Deeny starts alongside Baird in the second row.
Will Connors is back from injury to start at openside flanker, with James Culhane and Alex Soroka continuing in the back row.
Leinster: Ciarán Frawley; Andrew Osborne, Liam Turner, Jamie Osborne, Jimmy O'Brien; Ross Byrne, Fintan Gunne; Cian Healy, Rónan Kelleher (capt), Thomas Clarkson; Ryan Baird, Brien Deeny; Alex Soroka, Will Connors, James Culhane
Replacements: Gus McCarthy, Jack Boyle, Rabah Slimani, Diarmuid Mangan, Scott Penny, Cormac Foley, Charlie Tector, Ruben Moloney
Connacht show six changes to their side for Saturday's must-win meeting with the Lions in Johannesburg, as Shayne Bolton (above) returns from injury for Cullie Tucker's side.
Bolton missed the agonising defeat to the Stormers in Cape Town, but comes back in to replace Chay Mullins on the right wing.
There's one other change to the backline, with Matthew Devine getting a start at scrum-half to partner Jack Carty.
David Hawkshaw and Cathal Forde pair up in the centre again, while Piers O'Conor continues at full-back.
Dave Heffernan comes into the starting team at hooker, with Peter Dooley and Finlay Bealham continuing at prop.
There's a new second row partnership, with the bulk of Josh Murphy and Joe Joyce replacing Oisin Dowling and Darragh Murray.
Sean Jansen also comes back into the starting team at number eight, joining Conor Oliver and captain Cian Prendergast in the back row.
Connacht: Piers O'Conor; Shayne Bolton, David Hawkshaw, Cathal Forde, Shane Jennings; Jack Carty, Matthew Devine; Peter Dooley, Dave Heffernan, Finlay Bealham; Josh Murphy, Joe Joyce; Cian Prendergast (capt), Conor Oliver, Sean Jansen
Replacements: Eoin de Buitléar, Jordan Duggan, Sam Illo, Oisin Dowling, Paul Boyle, Colm Reilly, Hugh Gavin, Santiago Cordero,
Stuart McCloskey (above) has been passed fit for Ulster ahead of their final home game of the regular season against the Sharks on Saturday (live on RTÉ2 and RTÉ Player).
The centre was a late withdrawal from the side that were beaten by Leinster last week, but is fit to take his place alongside Jude Postlethwaite in midfield, as Richie Murphy's side look to get back into play-off contention.
Andrew Warwick, Alan O'Connor and Matty Rea all start in what will be their final home games for the province, with the trio confirmed to be leaving at the end of the season.
Warwick is in an unchanged front row alongside Rob Herring ad Tom O'Toole, while O'Connor again partners Cormac Izuchukwu at lock.
Rea comes in at blindside flanker, as James McNabney moves to number 8, with Nick Timoney on the openside. David McCann is on the bench, among a 6:2 split.
Nathan Doak and Jack Murphy continue in the half-backs, with McCloskey and Postlethwaite in midfield.
There is a reshuffle in the back three, with Mike Lowry out. Jacob Stockdale moves from left wing to full-back, while Zac Ward goes from right wing to left, and Werner Kok makes his first appearance since January, starting in the 14 shirt against his former side.
Ulster: Jacob Stockdale, Werner Kok, Jude Postlethwaite, Stuart McCloskey, Zac Ward; Jack Murphy, Nathan Doak; Andrew Warwick, Rob Herring, Tom O'Toole; Alan O'Connor, Cormac Izuchukwu; Matty Rea, Nick Timoney, James McNabney
Replacements: Tom Stewart, Callum Reid, Scott Wilson, Matthew Dalton, Kieran Treadwell, Dave Shanahan, Aidan Morgan, David McCann
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Watch a URC double-header, Scarlets v Leinster and Ulster v Sharks, on Saturday from 4.45pm on RTÉ2 and RTÉ Player
