Sam Warburton will make his first appearance of the season for Cardiff Blues against RaboDirect PRO12 champions Leinster on Friday night.
The flanker has not played since June 29 when he suffered a torn hamstring in the latter stages of the British & Irish Lions' 16-15 second Test defeat in Australia.
Warburton is one of five changes to the Blues starting XV for the fixture in Dublin with Harry Robinson returning to the left wing while Lloyd Williams is recalled from the bench and is paired at half back with Rhys Patchell.
A new look pack sees skipper Matthew Rees return to the starting line-up with prop Sam Hobbs making his first start this season at loosehead.
As for their opponents, Brian O'Driscoll has been named at outside centre in a Leinster side which includes three fellow British & Irish Lions in Cian Healy, Jamie Heaslip and Rob Kearney.
Ireland back Fergus McFadden and second row Quinn Roux have recovered from their respective injuries to also take their places in the starting XV.
Table-toppers Glasgow Warriors are the only side with a 100 percent winning record this season and they travel to the Stadio XXV Aprile in Parma to take on Zebre, who recorded an historic victory in Cardiff last time out.
Captain Al Kellock is back in the starting line-up after being stretchered off against the Blues three weeks ago.
Sean Maitland makes his first appearance of the season, while Gabriel Ascarate makes his first competitive start for the club in place of Mark Bennett, as Gregor Townsend makes nine personnel changes and one positional switch from the side that defeated Leinster last week.
Rory Best and Tommy Bowen have been selected for Ulster against Benetton Treviso at Ravenhill.
Altogether, there are 11 Ireland internationals in the starting XV and winger, Tommy Bowe said: "It is great to be back. It has been a tough old pre-season with my wrist injury but I am delighted to be playing."
Treviso head coach Franco Smith has made no changes to his 23-man squad following last weekend's impressive 29-19 victory over Munster.
Edinburgh head coach Alan Solomons hands 20-year-old scrum-half Sam Hidlago-Clyne his first start against Scarlets at Murrayfield with captain Greig Laidlaw out injured (knee).
Hidalgo-Clyne's selection is one of four personnel changes to the backline, with centre Ben Atiga returning in place of the injured Dougie Fife (head knock).
Lee Jones starts in place of injured wing Tim Visser (head knock), while fellow Scotland internationalist, Jack Cuthbert, is selected in place of Nikki Walker.
The travelling West Wales side have won their last four encounters against Scottish opponents and British and Irish Lions centre Jon Davies will captain his region for the first time this season.