Ferris, a late withdrawal from the side to face Connacht, slots back in at blindside flanker, with Faloon continuing at openside after Chris Henry, who was due to start, fell victim to an injury at training on Thursday. Thomas Anderson has been named amongst the replacements.
In the backs, the only change sees Andrew Trimble take over from the injured Simon Danielli on the left wing, as he did during the first half of the 30-6 win over Connacht. Mark McCrea has been added to the bench.
Paddy Wallace will captain Ulster once again as they look to maintain their position in the top four of the Magners League table.
The buzz word in the Ulster camp is 'focus', with head coach Brian McLaughlin emphasising the one game at a time approach as the province finish off their first leg of league games and then concentrate on their Heineken Cup opener next week at home to Bath.
"The most important thing of all is that we retain our focus and that means we can look no furtther than our game against the Scarlets on Friday," said McLaughlin.
"We were all very disappointed at losing to Edinburgh. There was a feeling we had played well without adding the final touches.
ULSTER (v Scarlets): Clinton Schifcofske; Timoci Nagusa, Darren Cave, Paddy Wallace (capt), Andrew Trimble; Ian Humphreys, Isaac Boss; Tom Court, Nigel Brady, BJ Botha, Ed O'Donoghue, Ryan Caldwell, Stephen Ferris, Willie Faloon, Robbie Diack.
Replacements: Andy Kyriacou, Declan Fitzpatrick, Neil McComb, Thomas Anderson, Paul Marshall, Ian Whitten, Mark McCrea.