With Paddy Wallace and Tom Court in camp with Ireland ahead of their Six Nations match against Scotland, Luke Marshall and Bryan Young come in to cover at inside centre and loosehead prop respectively.
Ireland Under-20 international Marshall forms a youthful centre partnership with the 20-year-old Nevin Spence, who will be making his 10th Magners League appearance.
"I'm just taking each game as it comes and trying to play to my potential," Spence told the Belfast Telegraph.
"Paddy Jackson did well last week and there is a lot of youth coming through with the likes of Craig Gilroy and Luke Marshall, so it looks good for the future.
"It's good that the coaches have just thrown us in and with Gilroy getting a good run, it shows we haven't done too bad and we're happy enough.
Ian Humphreys has recovered from a shoulder injury and is back in the team in place of youngster Paddy Jackson, who won his first cap last Friday against the Scarlets.
In the back row, Willie Faloon is recalled after being rested for last weekend's trip to the Welsh capital. He fills the openside flanker berth with Chris Henry moving to the blindside in place of the benched Thomas Anderson.
Tickets for Friday night's match are still available to purchase from www.ulsterrugby.com and all the usual outlets.
Gates open at 5.30pm and Ulster Rugby would advise supporters to avoid parking in the immediate vicinity of the Ravenhill grounds where restrictions may be in place. Instead, fans should make use of the Park 'n' Ride facilities at Pirrie Park and along Montgomery Road.
ULSTER (v Cardiff Blues): Adam D'Arcy; Andrew Trimble, Nevin Spence, Luke Marshall, Craig Gilroy; Ian Humphreys, Ruan Pienaar; Bryan Young, Andi Kyriacou, Declan Fitzpatrick, Johann Muller (capt), Tim Barker, Chris Henry, Willie Faloon, Pedrie Wannenburg.
Replacements: Nigel Brady, Paddy McAllister, Jerry Cronin, Ryan Caldwell, Thomas Anderson, Paul Marshall, Ian Whitten, Tommy Seymour.