The side will also be without vice-captain Williams who suffered a hamstring strain in a training session earlier this week having made his first regional appearance of the season last weekend.
Owen, who earlier this week signed a contract extension to remain at the region, has been named on the wing with Liam Williams moving to his preferred fullback position.
Edwards comes in to the front row, alongside captain Ken Owens and international loosehead Rob Evans, for the mammoth challenge at Thomond Park on Saturday.
The Scarlets will hope to secure a victory in the final game of the regular Guinness PRO12 season to keep hopes of a play-off spot alive. Scarlets will also be keeping a keen eye on the score, and result, at the Liberty Stadium as Ospreys welcome fourth place Ulster.
Speaking earlier this week Pivac said: "We've talked about the scenarios, in relation to our match and Ulster's match with Ospreys. We're going with focus of a quarter final, it's a must win match if we're to progress without worrying too much about other matches.
"We'll take the same approach as last week, get out there and focus on the performance and everything else should fall in to place."
Talking about Scarlets' opposition Pivac went on to say; "They've just had a good win against Edinburgh. They've got a very good driving line out. They'll be a tough side. They have some good attacking threats. They're a side that's going to be very challenging, especially at home."
Scarlets will take the confidence of important wins on the road this season to Munster this weekend. Pivac went on to say: "We talked about last year's top four, we've played three of them away and won all three. I think this game is slightly different from those - there's no more next week or second chances. We all know what we have to do which adds a little bit more pressure.
"Certainly, we have got the confidence of going, in particular to Ireland, Ulster was one of our best performances this season. It's going to require another massive effort."
Scarlets team to take on Munster at Thomond Park, Saturday 7th May, kick-off 3pm;
15 Liam Williams, 14 Gareth Owen, 13 Steff Hughes, 12 Hadeigh Parkes, 11 Steff Evans 10 Steve Shingler 9 Aled Davies, 1 Rob Evans, 2 Ken Owens ©, 3 Peter Edwards, 4 Jake Ball, 5 David Bulbring, 6 Lewis Rawlins, 7 James Davies, 8 John Barclay
Replacements: Ryan Elias, Dylan Evans, Rhodri Jones, Tom Price, Morgan Allen, Gareth Davies, Aled Thomas, Michael Tagicakibau
Unavailable through injury: Emyr Phillips (knee), Tom Williams (shoulder), Aaron Shingler (concussion), DTH van der Merwe (shoulder), Samson Lee (concussion), Mike Collins (hamstring), Scott Williams (hamstring)
Guinness PRO12 Scarlets News
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