Glasgow Warriors look as though they will have to go into their first Champions Cup quarter-final without the services of Scottish No 8 Josh Strauss.
The 30-year-old suffered a kidney injury in the RBS 6 Nations clash with France in Paris last weekend and has been sidelined for at least six weeks. He will then return to hospital for further tests.
The Warriors are due to travel to Allianz Park on Sunday, 2 April to face the Champions Cup holders Saracens. Such is the keen anticipation among the Glasgow fans that all 3,750 tickets allocated to the PRO12 club for the fixture have been sold, along with a few extras provided by the European champions.
Better news for Gregor Townsend's side is that Scottish international Peter Horne has signed a three-year deal to remain at the Warriors. The 27-year-old, who can play at stand-off or at centre, will be staying at Scotstoun until at least May, 2020.
Since making his debut against Ulster in 2009, Horne had made 106 appearances and scored 195 points for the club. He has also earned 23 caps and featured in all five Scottish games at the 2015 World Cup.
Horne returns to the Warriors starting XV for their PRO12 trip to Belfast this weekend having overcome an ankle injury that required surgery. Brandon Thomson will make his Glasgow Warriors debut at full-back having joined the club last week on a short term deal from the Stormers.
"Peter Horne is one of our hardest working players and a leader on and off the pitch, so his return will give everyone a boost. It's a credit to our medical staff that Peter and Tjiuee Uanivi are both available for what is a crucial match," said Warriors head coach Townsend.
"Brandon Thomson has integrated really well since his arrival and showed a good level of physicality while playing for Stirling County at the weekend. He has a very good rugby brain and is a quick learner, and is relishing the opportunity to play for the club.
"It's also great to be able to include Mark Bennett and Simone Favaro who both played Test match rugby last weekend. We will require everyone in our squad to play with huge commitment, effort and belief as we look to bounce back from last week's disappointing result."
Ulster Rugby: Louis Ludik; Tommy Bowe, Luke Marshall, Darren Cave, Craig Gilroy; Pete Nelson, Ruan Pienaar; Callum Black, John Andrew, Ricky Lutton, Pete Browne, Franco van der Merwe, Sean Reidy, Chris Henry (captain), Marcell Coetzee
Replacements: Rob Herring, Andrew Warwick, Wiehan Herbst, Kieran Treadwell, Robbie Diack, Paul Marshall, Jacob Stockdale, Jack Owens
Glasgow Warriors: Brandon Thomson; Lee Jones, Mark Bennett, Nick Grigg, Sean Lamont; Peter Horne, Henry Pyrgos; Alex Allan, James Malcolm, Sila Puafisi, Brian Alainu'uese, Scott Cummings, Rob Harley, Simone Favaro, Adam Ashe
Replacements: Corey Flynn, Jamie Bhatti, D'arcy Rae, Tjiuee Uanivi, Lewis Wynne , Grayson Hart, Richie Vernon, Rory Hughes
Champions Cup Quarter-Final
Sunday, 2 April
Saracens v Glasgow Warriors - Allianz Park (13:00 kick-off)