Parker Pen Challenge Cup Finalists Wasps are currently on an 11-match winning streak, with a win guaranteeing them a home semi-final, while even a defeat – other results permitting – would still see them finish the regular season above Sharks in second place, behind Gloucester.
Saturday sees the return of wing Kenny Logan, scrum-half Martyn Wood and hooker Phil Greening, meaning that John Rudd, Rob Howley and Trevor Leota drop out of the side respectively.
England squad centre Stuart Abbott is named in the side, but is an injury doubt after taking a heavy knock to the ribs during training, with Mark Denney set to deputise should he not make kick-off.
Winger Logan – this week called up by Scotland – said ahead of the match: "This month is vital for Wasps. We've done well to go 11 games unbeaten but there is still plenty work to do for the side if we want some silverware.
"Harlequins are a tough, physical side and will be looking to complete the double over us this season. However, we have all intentions of getting the home semi-final draw and make it 12 from 12."
London Wasps: 15 Mark Van Gisbergen, 14 Josh Lewsey, 13 Fraser Waters, 12 Stuart Abbott, 11 Kenny Logan, 10 Alex King, 9 Martyn Wood, 8 Lawrence Dallaglio (captain), 7 Paul Volley, 6 Joe Worsley, 5 Richard Birkett, 4 Simon Shaw, 3 Will Green, 2 Phil Greening, 1 Craig Dowd. Replacements: 16 Rob Howley, 17 Ayoola Erinle, 18 John Rudd, 19 Mark Lock, 20 Peter Scrivener, 21 Alistair McKenzie, 22 Trevor Leota.
Kick-off: 15.00 BST (14.00 GMT)