Rob Jewell replaces the injured George Harder on the right wing, while Josh Taumololo makes his first start in the Zurich Premiership at outside centre after injuring himself against Saracens in Quins' final pre-season warm up game. Taumololo replaces Andy Reay in the No.13 jersey.
Harlequins will be looking to add to their fantastic start to the season with another good performance against the Exiles.
Harlequins: 15 Gavin Duffy, 14 Rob Jewell, 13 Josh Taumalolo, 12 Mel Deane, 11 Ugo Monye, 10 Paul Burke, 9 Ben Willis, 8 Tony Diprose, 7 Andre Vos, 6 Pat Sanderson, 5 Simon Miall, 4 Bill Davison, 3 John Dawson, 2 Ace Tiatia, 1 Mike Worsley.Replacements: 16 Tani Fuga, 17 Ceri Jones, 18 Laurent Gomez, 19 Jim Evans, 20 Luke Sherriff, 21 Simon Keogh, 22 Andy Dunne.
Kick-off: 15.00 BST (14.00 GMT)