As a result, Jonny May, named in the England Saxons squad this week for the first time, moves into the full back berth.
Other changes see Eliota Fuimaono-Sapolu return to partner Mike Tindall in the Gloucester midfield and Dario Chistolini named at tight head.
With two wins from their four pool matches so far, it's a game that Gloucester need to win to have any chance of qualifying for the knock out stages.
However, Quins have been arguably the form team in England this season and won the previous encounter this season between these two sides in this competition.
Accordingly, it's going to be a huge challenge at the Stoop as acknowledged by Head Coach Bryan Redpath this week.
"We have to be realistic, Quins have been in great form this season but they've had a couple of tough results recently against admittedly some very good teams.
"It's a massive challenge for us going down there. We haven't performed well there in the past so we need to put in a performance that does us credit and gives us a chance to win.
"We need to take our chances against them which we didn't do in the first game at Kingsholm whereas they took everything that came their way that night.
"We were a bit lateral last weekend and we won't have that luxury against Harlequins. It's going to be a real challenge for us but one that we should look forward to.
Jonny May; Charlie Sharples, Mike Tindall, Eliota Fuimaono-Sapolu, James Simpson-Daniel; Freddie Burns, Rory Lawson; Nick Wood, Scott Lawson, Dario Chistolini; Jim Hamilton, Alex Brown; Alasdair Strokosch, Akapusi Qera, Luke Narraway (capt)
Darren Dawidiuk, Dan Murphy, Rupert Harden, Will James, Matt Cox, Dave Lewis, Ryan Mills, Henry Trinder