There is a top-versus-bottom clash at Sixways on Saturday as Aviva Premiership leaders Saracens travel to Worcester.
Alistair Hargreaves captains Saracens from lock, and is partnered by George Kruis in the second-row.
Elsewhere in the pack, Mako Vunipola returns to the starting XV and is joined by Schalk Brits and Matt Stevens in the front-row.
In the back row, Billy Vunipola returns to No 8, with Jackson Wray starting at blindside flanker and Kelly Brown completing the back-row trio.
In the backs, in-form Richard Wigglesworth continues at scrum-half and is partnered by Charlie Hodgson in the halves. Chris Wyles starts at inside centre and is partnered by Tim Streather, who faces his hometown club.
In the back-three, David Strettle returns to the side after shaking off a knock that ruled him out of last weekend's game against Leicester, and starts on the left wing. Jack Wilson swaps wings and replaces Chris Ashton on the right flank, whilst England international full-back Alex Goode starts at fifteen.
On the bench, Saracens welcome back England internationals Mouritz Botha and Brad Barritt from their respective injuries, whilst back-rower Justin Melck and scrum-half Ben Spencer make the 23-man squad.
For Worcester, centre Andy Symons will get his first Premiership start, one of two changes as Leonardo Senatore comes in for the injured Jonathan Thomas at No 8.
Semisi Taulava is recalled to the bench and could make his first appearance since October's clash with Newcastle.
Warriors players will be wearing their charity shirt for their fourth annual charity match as they continue to raise money for Acorns Children's Hospice.
In other action on Saturday, second-placed Northampton take on third-placed Bath in a high-profile clash at Franklin's Gardens.
The hosts welcome back three stalwarts to their starting XV, with captain Dylan Hartley and Courtney Lawes both returning to the pack, while George Pisi will wear the No 13 shirt following the end of his recent suspension.
Bath have made just one change to the starting line-up who beat Harlequins last weekend. Martin Roberts comes into the scrum-half position, with Peter Stringer shifting to the bench.
Jason Shoemark starts at centre for fifth-placed Exeter Chiefs as they prepare for the tough trip to Twickenham Stadium to face fourth-placed Harlequins.
The Chiefs have tweaked their line-up slightly with England international Tom Johnson returning to the back-row at the expense of Kai Horstmann and Shoemark also replacing Sam Hill. However, Horstmann is retained in the match-day 23 as he replaces Don Armand on the bench.
There are three changes to the Harlequins side that played Bath last week as centre Tom Casson, scrum half Danny Care and tighthead prop Will Collier return from injury to start.
Care, Mike Brown, Nick Evans, George Robson, Chris Robshaw and Nick Easter have participated in all of the club's Big Games to date and will all make their sixth appearance in the annual festive fixture.
Sixth-placed Leicester have recalled Dan Bowden, Owen Williams and Adam Thompstone to their back line for their clash against seventh-placed Sale Sharks at Welford Road.
International front-rows Marcos Ayerza, Tom Youngs and Dan Cole are back in the starting line-up. Louis Deacon captains the side in the absence of the injured Toby Flood and is joined in the second-row by Ed Slater.
Sale, meanwhile, are without Danny Cipriani for the trip so Nick Macleod wears No 10, alongside scrum-half Dwayne Peel.
Making his debut in the game will be Tongan No 8 Viliami Fahiki, who joined the club last month.
Mark Cueto moves to the centre to cover for the injured Mark Jennings and Charlie Ingall is recalled on the right wing after an impressive game at Saracens in November.