Ulster's Challenge Cup hopes have been dealt a blow with the news that skipper Iain Henderson will miss out on Sunday's last-16 clash with Harlequins at the Twickenham Stoop, however their hosts will be far from full strength for the knock-out tie.
Ulster's head coach Dan McFarland had indicated Henderson was fully expected to be involved during his media briefing earlier this week but the side will instead once again have to do without their influential Irish international lock who picked up a shoulder knock against England last month.
Fly-half Billy Burns has, however, overcome the injury he himself sustained on Six Nations duty to take his place in the ten jersey, meaning Mike Lowry reverts to full-back having played at ten for the previous two games.
Elsewhere, it's as expected for the northern province with Rob Herring and Jacob Stockdale coming back into the side after their own Ireland exertions.
That means returns for Stuart McCloskey alongside James Hume in midfield, with Herring slotting in between props Eric O'Sullivan and Marty Moore.
Alan O'Connor and Kieran Treadwell are in the engine room with no Henderson or Sam Carter and it's Jordi Murphy who will captain the side in a back-row that also includes Nick Timoney and Sean Reidy.
John Cooney will again take on a side he excelled against twice last season from the number nine jersey while Rob Baloucoune joins Stockdale and Lowry in the back-three for what will be his first European action since January 2020.
Harlequins, meanwhile, have made clear where their priorities lie, making 14 changes to the side that lost to Bristol at Ashton Gate last week.
Like Ulster, their own skipper, Stephan Lewies is unavailable but the absence of the likes of Danny Care, Marcus Smith, Mike Brown, Joe Marler, Wilco Louw, Scott Baldwin, Andre Esterhuizen and Joe Marchant are not injury-related.
With seven rounds of Premiership action still to go, and 'Quins presently occupying the fourth and final play-off place, their front-line stars will get the week off, although there is one familiar face in the team with former Ulster number ten Brett Herron getting a start at fly-half.
15. Tyrone Green; 14. Luke Northmore, 13. James Lang, 12. Paul Lasike, 11. Nathan Earle; 10. Brett Herron, 9. Scott Steele; 1. Santiago Garcia Botta, 2. Elia Elia, 3. Will Collier; 4. Hugh Tizard, 5. George Hammond; 6. Archie White, 7. Jack Kenningham, 8. Tom Lawday (captain).
Replacements: 16. George Head, 17. Jordan Els, 18. Simon Kerrod, 19. Tevita Cavubati, 20. Matas Jurevicius, 21. Jack Stafford, 22. Ben Tapuai, 23. Ross Chisholm.
15. Michael Lowry; 14. Robert Baloucoune, 13. James Hume, 12. Stuart McCloskey, 11. Jacob Stockdale; 10. Billy Burns, 9. John Cooney; 1. Eric O'Sullivan, 2. Rob Herring, 3. Marty Moore; 4. Alan O'Connor, 5. Kieran Treadwell; 6. Sean Reidy, 7. Jordi Murphy (captain), 8. Nick Timoney.
Replacements: 16. John Andrew, 17. Andrew Warwick, 18. Tom O'Toole, 19. Cormac Izuchukwu, 20. Matty Rea, 21. Alby Mathewson, 22. Ian Madigan, 23. Ethan McIlroy.