Roger Wilson could make his first appearance for Ulster since returning to the province after being selected on the bench.
Marshall's inclusion at scrum half will see Ruan Pienaar move to out-half in place of Paddy Jackson who is listed among the replacements.
Tommy Bowe shifts to the full-back spot, with Jared Payne earning a well-earned rest after playing in every minute of Ulster's 2012/13 campaign to date.
Gilroy is named on the left wing as Andrew Trimble switches to the right, while Paddy Wallace and Darren Cave continue their impressive centre partnership.
Fitzpatrick replaces All Black John Afoa at tighthead prop to join Rory Best and Tom Court in the front row. Behind that trio, Stevenson steps in for the injured Johann Muller in the second row.
The back row remains unchanged from the one that lined out against Glasgow Warriors last time out, although Chris Henry will have the added responsibility of captaining the side in Muller's absence.
The decision has been made not to risk Stephen Ferris (back) despite him being able to train earlier in the week.
ULSTER (v Newport Gwent Dragons): Tommy Bowe; Andrew Trimble, Darren Cave, Paddy Wallace, Craig Gilroy; Ruan Pienaar, Paul Marshall; Tom Court, Rory Best, Declan Fitzpatrick, Lewis Stevenson, Dan Tuohy, Iain Henderson, Chris Henry (capt), Nick Williams.
Replacements: Nigel Brady, Callum Black, John Afoa, Mike McComish, Roger Wilson, Paddy Jackson, Luke Marshall, Jared Payne.