Roger Wilson will make his 150th appearance for the province in the game and starts at blindside flanker.
The match will also see a first start for centre Stuart McCloskey who came on as a replacement in the win over the Newport Gwent Dragons a fortnight ago.
Jared Payne starts at full-back with Tommy Bowe, who scored two tries on his return against the Dragons, named on the right wing and former Ireland Under-20 international Rory Scholes continuing on the left wing.
The man-of-the-match from the Dragons clash, Darren Cave, is selected in midfield alongside the 21-year-old McCloskey.
Ruan Pienaar combines at half-back with Paddy Jackson, who has been released from international duty.
In the pack, John Afoa returns to the starting line-up where he joins Callum Black and Rob Herring in the front row.
Captain Johann Muller starts in the second row and is partnered by Robbie Diack who will don the number 5 jersey.
Sean Doyle starts at openside flanker with Wilson at blindside and the returning Nick Williams named at number 8.
The fit-again Ferris is joined on the bench by fellow forwards Niall Annett, Tom Court, Ricky Lutton and Lewis Stevenson, with backs Michael Heaney, Craig Gilroy and Ricky Andrew completing the matchday squad.
ULSTER (v Scarlets): Jared Payne; Tommy Bowe, Darren Cave, Stuart McCloskey, Rory Scholes, Paddy Jackson, Ruan Pienaar; Callum Black, Rob Herring, John Afoa, Johann Muller (capt), Robbie Diack, Roger Wilson, Sean Doyle, Nick Williams.
Replacements: Niall Annett, Tom Court, Ricky Lutton, Lewis Stevenson, Stephen Ferris, Michael Heaney, Craig Gilroy, Ricky Andrew.