Ulster have made two changes for the return Champions Cup match against Harlequins at The Stoop.

Matt Faddes starts on the right wing and lock Kieran Treadwell also returns while Craig Gilroy and Alan O'Connor are the duo to drop out.

Kyle Sinckler will captain Quins in his first home appearance of the season and prop Santiago Garcia Botta is back after his recent wedding.

Ulster beat the English side 25-24 last weekend in Belfast.

Quins have lost their opening three games while Ulster boast a 100% record to top Pool Three.

The inclusion of Faddes sees Louis Ludik switch to Ulster's left wing while Jacob Stockdale remains at full-back.

Will Evans returns for Harlequins after being rested for the last two weeks and James Chisholm is back on the bench following his rehabilitation from injury.

Argentina scrum-half Martin Landajo starts alongside Brett Herron, who makes his first Heineken Champions Cup appearance for the club with Fiji winger Vereniki Goneva also starting his first game for the quarters, on the opposite wing to the returning Cadan Murley.

"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," said Paul Gustard, Harlequins' head of rugby.

"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 on Friday night.

"It is a great opportunity for a couple of our players who are returning from injury to move the jersey forward in what is a must-win game for us if we are to have a chance of competing in this competition."

Harlequins: Ross Chisholm, Vereniki Goneva, James Lang, Francis Saili, Cadan Murley, Brett Herron, Martin Landajo; Santiago Garcia Botta, Elia Elia, Kyle Sinckler, Stephan Lewies, Tevita Cavubati, Will Evans, Semi Kunatani, Alex Dombrandt.

Replacements: Jack Musk, Nick Auterac, Simon Kerrod, Dino Lamb, James Chisholm, Niall Saunders, Paul Lasike, Travis Ismaiel.

Ulster: Jacob Stockdale, Matt Faddes, Luke Marshall, Stuart McCloskey, Louis Ludik, Billy Burns, John Cooney; Eric O'Sullivan, Rob Herring, Marty Moore, Kieran Treadwell, Iain Henderson (Capt.), Sean Reidy, Jordi Murphy, Marcell Coetzee.

Replacements: Adam McBurney, Andrew Warwick, Tom O'Toole, Alan O'Connor, Matthew Rea, David Shanahan, Bill Johnston, Craig Gilroy.