Ronan McCormack and Nigel Brady join Simon Best in the front row in place of Rod Moore and Paul Shields who are both named on the bench, with Best switching to tighthead prop.
With Roger Wilson, who picked up a knock against The Dragons last Friday, Andy Ward and Neil McMillan all ruled out through injury, McCall has opted for newcomer Gary Brown at No.8 with Matt Mustchin providing back-row cover from the bench. Brown is a 24-yr old from Belfast Harlequins with just one Ulster cap to date, so it's a big step for him.
Ulster: 15 - Bryn Cunningham; 14 - Tommy Bowe; 13 - Kevin Maggs; 12 - Paul Steinmetz; 11 - Tyrone Howe; 10 - David Humphreys (Captain); 9 - Kieran Campbell; 1 - Ronan McCormack; 2 - Nigel Brady; 3 - Simon Best; 4 - Gary Longwell; 5 - Matt McCullough; 6 - Campbell Feather; 7 - Neil Best; 8 - Gary Brown
Replacements: 16 - Paul Shields; 17 - Rod Moore; 18 - Rowan Frost; 19 - Matt Mustchin; 20 - Neil Doak; 21 - Paddy Wallace; 22 - Jonathon Bell