Anderson will captain the side from openside flanker in a back row which is completed by South African number 8 Robbie Diack, who has recovered from an ankle injury.
Prop Fitzpatrick is set for his first runout in an Ulster jersey since injurying his calf against Aironi Rugby in September, while full-back Jamie Smith also returns from a spell out with a shoulder problem.
Fitzpatrick joins Phoenix Academy duo Niall Annett and Conor Carey in the front row, and there is more Academy talent on the replacements bench in the form of John Burns, Ian Henderson, David McGuigan, Blane McIlroy, James McKinney and David McIlwaine.
Saturday's game is the first of two consecutive weeks of British & Irish Cup action, with the Ravens entertaining Moseley at Ravenhill next Friday (kick-off 4pm).
Gary Longwell's side got their Pool C campaign off to a winning start in October courtesy of a 32-12 triumph over Swansea at St. Helen's.
ULSTER RAVENS (v Bedford Blues): Jamie Smith; Craig Gilroy, Michael Allen, Luke Marshall, Tommy Seymour; Paddy Jackson, Ian Porter; Conor Carey, Niall Annett, Declan Fitzpatrick, Neil McComb, Ryan Caldwell, Thomas Anderson (capt), Ali Birch, Robbie Diack
Replacements: John Burns, Jerry Cronin, Ian Henderson, David McGuigan, Blane McIlroy, James McKinney, Chris Cochrane.