London Welsh coach Lyn Jones has made three changes to his squad for Sunday's Premiership clash with Harlequins at the Kassam Stadium.
The Exiles face a tough task against the reigning champions and will be hoping for a strong performance after a defeat at home to their local rivals London Wasps last weekend.
At number eight Adam Balding gets the nod over Alfie To'oala who moves back to the bench.
Tighthead prop Paulica Ion returns to the run-on side after being out with a knee injury, and Michael Hills comes in at openside flank to replace Mike Denbee.
The match day squad also sees the return of the influential Tyson Keates and the international experience of Tom Voyce.
London Welsh's last outing against Harlequins resulted in heavy defeat at the start of the season.
However the Exiles are a much improved team from the one that faced the Quins in September and will hope to use the home crowd to their advantage.
"We've taken on board a lot of lessons from our first game against Harlequins," said Jones.
"We have progressed and developed as a side and have made great improvements in our discipline and our kicking game.
"We are aware they are a very confident side and are top of the League at the moment, we are disappointed after last week and are keen to make amends."
Meanwhile, Harlequins boss Conor O'Shea has made six changes to the team that defeated London Irish in Big Game 5 at Twickenham Stadium last weekend.
Among the backs Ollie Lindsay-Hague comes in for Mike Brown at full-back, while Jordan Tuner-Hall and George Lowe form the centre partnership in place of Tom Casson and Matt Hopper, with the latter named on the bench.
The final change in the back-line sees Sam Smith taking over from Ugo Monye on the left wing.
In the forwards Charlie Matthews comes in for Olly Kohn in the second row while Tom Guest starts at blindside flanker in place of Maurie Fa'asavalu.
Form: London Welsh have slipped to back to back Aviva Premiership defeats, but at Kassam Stadium the Exiles have won two of their last three games. Harlequins, the defending Premiership champions, have topped the table since round seven. Quins' only defeat in their last six encounters in the competition was 18-21 at Bath on 23 November. Harlequins won 40-3 when the two clubs met at the Twickenham Stoop in round two. London Welsh's only previous victory over Harlequins in a competitive match was in September 1972 with a 45-12 victory at Twickenham in the 1st round of the RFU Knockout Cup.
London Welsh: 15 Tom Arscott, 14 Dan Caprice, 13 Seb Jewell, 12 Sonny Parker, 11 Nick Scott, 10 Gordon Ross, 9 Rob Lewis, 8 Adam Balding, 7 Michael Hills, 6 Ed Jackson, 5 Kirill Kulemin, 4 Jonathon Mills (c), 3 Paulica Ion, 2 Neil Briggs, 1 Frank Montanella.
Replacements: 16 Greg Bateman, 17 Tom Bristow, 18 James Tideswell, 19 Matt Corker, 20 Alfie To'oala, 21 Tyson Keates, 22 Alex Davies, 23 Tom Voyce.
Harlequins: 15 Ollie Lindsay-Hague, 14 Tom Williams, 13 George Lowe, 12 Jordan Turner-Hall, 11 Sam Smith, 10 Nick Evans, 9 Danny Care, 8 Nick Easter, 7 Chris Robshaw (c), 6 Tom Guest, 5 George Robson, 4 Charlie Matthews, 3 James Johnston, 2 Joe Gray, 1 Joe Marler.
Replacements: 16 Rob Buchanan, 17 Mark Lambert, 18 Will Collier, 19 Sam Twomey, 20 Luke Wallace, 21 Karl Dickson, 22 Ben Botica, 23 Matt Hopper.
Date: Sunday, January 6
Venue: Kassam Stadium
Referee: Llyr Ap Geraint-Roberts
Assistant referees: Paul Dix, Robin Goodliffe
Timekeeper: Tony Turner
Assessor: Ed Morrison