England team-mates Mako Vunipola and Jamie George, both of whom began the Quins game on the bench but made late impacts, start.
Another notable absence is centre Nick Tompkins, who made his 150th appearance for the club last weekend. His place is taken by Duncan Taylor in the only change to the backs.
Director of rugby Mark McCall has made three additions to his pack, with Andy Christie coming into the back row and McFarland slotting into second row in place of Itoje.
Gloucester similarly fought back in their season opener, as they recovered from 21-0 down against Wasps for a 27-21 victory.
Wasps, who play at Bath tonight, face an anxious wait over their future with the club on the brink of administration with a tax bill owing to HMRC.
Former Wasps and England backrower James Haskell fears the worst. He said: “I hope it’s not true, I hope there’s a last-minute saviour to ride over the hill to take Wasps out of this trouble.
“Unfortunately, I think it [administration] is going to happen, which comes with a whole load of sanctions. My thoughts firstly are with all the players.”