Kingspan defeat is a spur: Gustard
England forward Kyle Sinckler will captain Harlequins on his first home appearance of the season in the second part of the double-header with Ulster.
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Santiago Garcia Botta returns at loosehead after his recent wedding and flanker Will Evans also starts after being rested for a fortnight.
Harlequins head of rugby Paul Gustard said: "We were disappointed to come away with the one-point loss in Ulster last weekend and we have been working hard this week to assess the critical few and put our energy into those.
"The players have taken good ownership of the week and driven the detail and energy. We look forward to welcoming Ulster to what we hope will be a noisy Stoop."
Elsewhere in the Champions Cup, Ospreys travel to Racing 92 hoping to avenge their 40-19 defeat at the Liberty Stadium.
Ospreys have made seven changes for the match in Paris, with Cai Evans returning at full-back and Lesley Klim and Luke Morgan on the right and left wing respectively.
Kieran Williams and Tiaan Thomas-Wheeler make up a youthful combination in the centres, with Shaun Venter at scrum-half and Marty McKenzie at fly-half.
With Ulsterman Allen Clarke no longer coach, the Welsh club, who are out of contention, have vowed to continue blooding their young players.
Ospreys forwards coach Carl Hogg explained: "The players worked incredibly hard to qualify for the Heineken Champions Cup and we have to make sure we are respectful of the competition. But we understand where we stand in the pool.
"Over the last two or three months, younger players have had an opportunity because of the injuries, and have had chances to play in games they probably wouldn't have played in.
"But that stands us in really good stead for the future."