Experienced lock Michael Swift, the longest serving player in the current squad, is also included among the replacements as Mike McComish comes into the back row, with Mike McCarthy switching to the second row.
Speaking ahead of Friday's crucial encounter, Connacht coach Michael Bradley said: "The Scarlets have showed some good form in the Heineken Cup, with two wins from two - in particular the win over London Irish.
"They had a good, solid performance at home against the Dragons last week, which gives them three wins out of three coming into our match. So they'll be coming over with a lot of confidence.
"We managed to get back into the game, only to concede a late try and get nothing out of the match.
"Friday's game is a big one for us, it finishes off this end of the calendar - in terms of the Magners League and European matches - so it's important that we get a home win."
CONNACHT (v Scarlets): Gavin Duffy; Troy Nathan, Niva Ta'auso, Keith Matthews, Fionn Carr; Ian Keatley, Frank Murphy; Brett Wilkinson, Sean Cronin, Robbie Morris, Mike McCarthy, Bernie Upton, John Muldoon (capt), Johnny O'Connor, Mike McComish.
Replacements: Adrian Flavin, Jamie Hagan, Michael Swift, Andrew Browne, Conor O'Loughlin, Miah Nikora, Liam Bibo.