Nick Evans will start for Harlequins as they look to keep their LV= Cup hopes alive at home to Bath at the Stoop.
For Quins, 12 of the starting 15 have come through the Harlequins Academy, including the whole of the pack.
Mark Lambert, himself a product of the Development System, will captain the senior side for the first time on his 160th appearance for the club.
Among the replacements, Matt Shields comes into the side on loan from Darlington Mowden Park RFC.
Meanwhile academy trio Will Homer, Rory Jennings and Beno Obano are set to make their senior Bath debuts in the clash.
Scrum-half Homer and fly-half Jennings – who were recently included in the England U20s Six Nations squad alongside Bath teammates Max Clark and Charlie Ewels – both start, with prop Obano on the bench.
The back three is made up of fullback Horacio Agulla and wings Rich Lane and Olly Woodburn. Matt Banahan and Max Clark form the Bath midfield.
Nick Auterac, Tom Dunn and Kane Palma-Newport comprise the front row. In the second row are Dom Day and Charlie Ewels. Guy Mercer captains the side at openside, joined in the back row by blindside Alafoti Fa’osiliva and number eight David Sisi.
The club’s latest recruit, prop Max Lahiff, is named among the replacements.
Harlequins: 15 Ross Chisholm, 14 Tom Williams, 13 Tom Casson, 12 Harry Sloan, 11 Charlie Walker, 10 Nick Evans, 9 Karl Dickson, 8 James Chisholm, 7 Jack Clifford, 6 Joe Trayfoot, 5 Sam Twomey, 4 George Merrick, 3 Mark Lambert (c), 2 Rob Buchanan, 1 Darryl Marfo
Replacements: 16 Joe Gray, 17 Seb Adeniran-Olule, 18 Matt Shields, 19 Kieran Treadwell, 20 Henry Cheeseman, 21 Jordan Burns, 22 Ben Botica, 23 Ollie Lindsay-Hague
Bath: 15 Horacio Agulla, 14 Olly Woodburn, 13 Max Clark, 12 Matt Banahan, 11 Richard Lane, 10 Rory Jennings, 9 Will Homer, 8 David Sisi, 7 Guy Mercer (c), 6 Alafoti Fa’osiliva, 5 Charlie Ewels, 4 Dominic Day, 3 Kane Palma-Newport, 2 Tom Dunn, 1 Nick Auterac
Replacements: 16 Tom Woolstencroft, 17 Beno Obano, 18 Max Lahiff, 19 Tom Ellis, 20 Max Northcote-Green, 21 Micky Young, 22 Peter Stringer, 23 George Wacokecoke
Date: Saturday, January 31
Kick-off: 14:40 GMT
Venue: Twickenham Stoop
Referee: Ben Whitehouse (Wales)
Assistant referees: Jonathan Healy (England), Paul Burton (England)
Television match official: Stuart Terheege (England)
Timekeeper: Roy Marfleet (England)