In the Ulster pack, Nigel Brady comes in for Andy Kyriacou in a straight swap at hooker, the fit-again Ryan Caldwell replaces Dan Tuohy in the second row and in the back row Lion Stephen Ferris will make his second start of the season, lining up alongside Willie Faloon and Robbie Diack.
Ferris, a late withdrawal from the side to face Connacht, slots back in at blindside flanker, with Faloon continuing at openside as Chris Henry, who was due to start, picked up 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.
Meanwhile, the Scarlets have brought 2009 Lion Stephen Jones into their starting line-up for the trip to Belfast.
Head coach Nigel Davies has chosen to bring back the influential out-half a week before the Scarlets' opening Heineken Cup game at home to Brive.
Jones was rested as a precaution for last weekend's high profile Welsh derby in Cardiff, to recover from a slight ankle injury.
The Scarlets will rest captain Mark Jones, who picked up a dead leg against the Blues, as well as player-coach Simon Easterby who left the field after aggravating a knee problem.
Flanker Johnathan Edwards makes his first start of the season ahead of Richie Pugh at openside, and Wales prop Rhys Thomas also returns to the side having missed the last two matches with stitches in a cut knee.
ULSTER: 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.
SCARLETS: Rhys Priestland; Sean Lamont, Gareth Maule, Jonathan Davies, Lee Williams; Stephen Jones, Martin Roberts; Iestyn Thomas, Matthew Rees, Rhys Thomas, Vernon Cooper, Lou Reed, Dafydd Jones, Johnathan Edwards, David Lyons (capt).
Replacements: Phil John, Ken Owens, Damian Welch, Josh Turnbull, Richie Pugh, Daniel Evans, Rob Higgitt.
Referee: Peter Allan (Scotland)
Assistant Referees: Dudley Phillips, Barry O'Keeffe (both Ireland)
Television Match Official: Marshall Kilgore (Ireland)
Match Odds (Paddy Power): Ulster to win: 8/15; Draw: 20/1; Scarlets to win: 6/4
Nigel Davies (Scarlets) - "Stephen (Jones) will play for us on Friday which will give him an opportunity to roll into the European game. He's massive for us - he has that level of experience and mental toughness on the field that we need for this game.
"He brings a real composure and understanding to the team. It's not only what he does on the field, it is what he contributes off the field as well and is hugely respected by all the guys and he does boss games particularly well.
"It's a short turnaround for us, however we are comfortable, we know where we are and what we want to do.
"We are going to have to be that much better than them to win up there and be on top form to get a result; but in any case that's where we need to be now going into Europe."
Top Scorers - 2009/10 Magners League: Ulster - Points: Ian Humphreys 29; Tries: Simon Danielli 2; Scarlets - Points: Rhys Priestland 21; Tries: Sean Lamont, Phil John, Daniel Evans, Mark Jones, Deacon Manu, David Lyons, Jonathan Davies 1 each
RECENT LEAGUE MEETINGS:
Saturday, September 2, 2006 - Ulster 31 Scarlets 16, Ravenhill
Saturday, March 3, 2007 - Scarlets 17 Ulster 11, Stradey Park
Friday, October 12, 2007 - Scarlets 32 Ulster 8, Stradey Park
Friday, February 29, 2008 - Ulster 20 Scarlets 8, Ravenhill
Friday, September 5, 2008 - Ulster 9 Scarlets 16, Ravenhill
Saturday, May 16, 2009 - Scarlets 43 Ulster 17, Parc y Scarlets
- Ulster won 30-6 at Connacht last Friday but have not won successive Magners League games for almost 12 months
- The Ulstermen are struggling at home just now, having slipped to three consecutive defeats. But Ulster won 20-16 the last time they played a Welsh team (the Ospreys at Liberty Stadium in round two)
- The Scarlets have recorded three successive losses but have, at least, picked up a losing bonus point in the last two
- The Welshmen's only away win in the Magners League since early January was a 30-9 triumph at Cardiff Blues on May 13
- The Scarlets have won four of their last five contests with Ulster in the Magners League, and won at Ravenhill for the first time in league competition on their most recent visit on September 5, 2008