Round six of the RaboDirect Pro12 campaign sees the top two teams - Glasgow and Munster - clash on Friday night.
Munster boss Rob Penney has rung the changes to his starting XV for the showdown with leaders Glasgow Warriors at Scotstoun Stadium.
Backs Andrew Conway, Ivan Dineen and Ronan O'Mahony return to senior action after impressing for the Munster 'A' side in the last two weeks, while JJ Hanrahan starts alongside Conor Murray at half-back.
Johne Murphy and Keith Earls, who were on the wings for last weekend's Heineken Cup win over Gloucester, make positional switches to full-back and outside centre respectively. Munster start with a new front-row with prop James Cronin making his third league start.
Meanwhile, Sean Lamont returns to the Glasgow Warriors starting line-up for the top of the table clash. Duncan Weir replaces Ruaridh Jackson at fly-half, while Chris Cusiter comes in for Niko Matawalu at scrum-half and will captain the side.
There are fourth other games on Friday and Ulster boss Mark Anscombe has made two personnel changes and one positional switch to the team that beat Montpellier for the home clash with Cardiff Blues.
Jared Payne moves from full-back to outside centre, with Darren Cave selected on the bench. Stuart Olding starts his first game for Ulster at 15. Up front, Callum Black starts at loosehead with Tom Court, who was named in Joe Schmidt's Ireland squad this week, moving to the bench.
For Cardiff, Richard Smith is handed his first start of the RaboDirect Pro12 season. Smith is named on the wing, replacing the injured Alex Cuthbert, as Blues make two changes to the side that defeated European champions Toulon last weekend.
The other changes to the starting line-up sees Dafydd Hewitt comes in at centre for Owen Williams, with Cory Allen moving to outside centre.
Welsh derby showdown
The Ospreys have named Matthew Morgan at fly-half for their Welsh derby against the Dragons in Swansea.
Morgan's promotion sees Dan Biggar move to full-back as Richard Fussell drops out of the squad altogether. Ashley Beck is also absent. Up front, Aaron Jarvis replaces Wales prop Adam Jones while Morgan Allen wears eight in place of Joe Bearman.
Lyn Jones has made a number of changes to his team. Tom Prydie is on the wing while centre Lewis Robling makes his season debut. Young gun Sam Parry steps in as hooker and Jevon Groves moves to flanker.
Edinburgh welcome four capped internationalists into their starting XV for the clash with Treviso at Murrayfield.
Number eight David Denton (arm), centre Matt Scott (thigh) and back-row Dimitri Basilaia (groin) are clear of the ailments that ruled them out of last weekend's loss to Perpignan, while full-back Greig Tonks - who returned from a hamstring injury with an appearance from the bench in that clash - starts his first match in a month.
Treviso head coach Franco Smith has reshuffled his starting XV after last weekend's loss to Leicester at Welford Road. Marco Fuser replaces Valerio Bernabo in the second row while Manoa Vosawai moves from the flank to number eight.
Finally, Italian outfit Zebre welcome back veteran prop Salvatore Perugini as they host the Scarlets.
The Welshmen have opted to move their highly successful half-back duo to the bench for this weekend's clash after significant game time in Europe. Rhys Priestland is back to his best form managing the Scarlets game including putting 16 points on the board from his boot last weekend against Racing Metro.
Gareth Davies comes back from injury to start at nine, with Steve Shingler given the 10 jersey and ahead of an important home fixture against Ulster next weekend at Parc y Scarlets. Romanian international prop Horatiu Pungea gets his first start.