Leicester take on Northampton in a top-of-the-table clash in the Aviva Premiership on Saturday, while there is a bottom-of-the-table battle between Worcester and Newcastle.
As the competition enters Round Five, third-placed Leicester show just one change to the side that accounted for Exeter at Sandy Park last weekend, with lock Graham Kitchener taking over from England
international Geoff Parling, who is on the bench.
Scrum-half David Mele and number eight Thomas Waldrom, who both missed the Exeter game, are also on replacement duty for the reigning champions.
Northampton rugby director Jim Mallinder makes two changes from the side that accounted for Sale Sharks last time out, with flanker Tom Wood and lock Samu Manoa both restored to the pack.
Hooker Dylan Hartley skippers second-placed Saints as Northampton meet Leicester for the first time since he was sent off in last season's Premiership final.
Top-of-the-table Saracens host ninth-placed London Wasps aiming to maintain their four point lead over the chasing pack.
England full-back Alex Goode will start at fly-half for the hosts, with Charlie Hodgson injured and Owen Farrell on bench duty.
Elsewhere, scrum-half Neil de Kock replaces Richard Wigglesworth, wing Michael Tagicakibau is in for David Strettle and Ben Ransom wears the number 15 shirt.
Up front, prop James Johnston makes his first Saracens start and Will Fraser features in the back-row.
For Wasps, flanker Sam Jones misses the trip to Allianz Park due to injury, so a reshuffled back-row sees Ed Jackson starting and Ashley Johnson switching from blindside to openside. Fly-half Joe Carlisle makes his first start since signing from Worcester and centre Charlie Hayter is recalled.
Lock George Skivington returns to action for tenth-placed London Irish as they host fifth-placed Harlequins.
Former Cardiff Blues prop John Yapp is handed a full debut for the Exiles alongside front-row colleagues David Paice and Leo Halavatau.
Also in the pack, Kieran Low moves from the back-row to partner Skivington, with Blair Cowan, Ofisa Treviranus and Chris Hala'ufia forming the breakaway trio.
Quins show three changes - all behind the scrum - after they lost at home to Saracens six days ago. Sam Smith starts on the right-wing, replacing Tom Williams, with Matt Hopper taking over from injured centre George Lowe and scrum-half Karl Dickson in for Danny Care.
In the bottom-of-the-table clash, rock-bottom Worcester host Newcastle looking to close the four-points gap to the Falcons.
Prop Jeremy Becasseau returns for the Warriors as the solitary change from last weekend's defeat against Wasps.
Worcester, who are without a Premiership win since March 1, parade new signing Paul Warwick on the bench, where Scotland international centre Alex Grove also features following an injury lay-off.
Newcastle rugby director Dean Richards makes two changes, both in the pack, as Falcons look to compound Worcester's misery at the Premiership basement. Rob Vickers replaces loosehead prop Franck Montanella and Carlo del Fava returns to the second-row, where he will partner Dom Barrow.