McCall welcomes back Andrew Trimble and Tommy Bowe to the backline while Bryn Cunningham has been left out of the squad to make way for Mark Bartholomeusz starting at fullback.
Neil Best makes his first Ulster start of this season replacing Stephen Ferris and Ferris drops to the bench. Matt McCullough is back in the starting 15 replacing Tim Barker who has dropped to the bench and Neil McMillan replaces Kieron Dawson and Dawson drops to the bench.
ULSTER: 15 - Mark Bartholomeusz; 14 -Tommy Bowe; 13 - Paul Steinmetz; 12 - Paddy Wallace; 11 - Andrew Trimble; 10 - David Humphreys; 9 - Isaac Boss;
1 - Justin Fitzpatrick; 2 - Rory Best; 3 - Bryan Young; 4 - Justin Harrison (Captain); 5 - Matt McCullough; 6 - Neil Best; 7 - Neil McMillan; 8 - Roger Wilson
Replacements: 16 - Paul Shields; 17 - Declan Fitzpatrick; 18 - Tim Barker; 19 - Stephen Ferris; 20 - Kieron Dawson; 21 - Kieran Campbell; 22 - Kevin Maggs
Meanwhile Edinburgh Rugby Ltd is officially dropping Gunners from its team name. The team will now simply be known as Edinburgh.
There are a number of reasons for the change, one of which is that the word Gunners is already a registered Trademark of Arsenal football club.
Edinburgh is the name by which the team was known back in 1872 when they played Glasgow in the world's first ever inter-district match. The capital side won that day, by three points to nil. The two cities meet again tonight in the fifth round of the Magners League at Murrayfield.