Sharples has yet to feature in this season's competition, with Chris Ashton and David Strettle preferred on the flanks for the wins over Scotland and Italy.
And a dead leg means Sharples will not have a chance to press him claims for inclusion for the mouth-watering encounter between the two unbeaten sides.
Lee Mears is also likely to miss the match with the Bath hooker suffering a bicep injury.
As a result Harlequins No.2 Chris Brooker was called up on Monday to train with the squad at Pennyhill Park.
Like Sharples, though, Mears has been unable to breaking into the match-day squad - with Dylan Hartley and Rob Webber ahead of him in the pecking order.