Scarlets head coach Wayne Pivac welcomes back hooker Wales Ken Owens who will lead the side in Saturday's clash with Connacht.
Apart from Owens' return, Jordan Williams, who has been named in the LV= Cup Breakthrough Player shortlist, will start at fullback whilst namesake Liam is on Wales duty.
Speedster Harry Robinson joins Michael Tagicakibau on the wings with former Auckland captain Hadleigh Parkes lining up alongside fellow Kiwi Regan King in the centre for the first time.
The halfback combination of Steven Shingler and Aled Davies will be looking to get their backline firing.
An experienced front row of Phil John, Owens and Peter Edwards will form a solid platform for second row pairing Lewis Rawlins and Johan Snyman with Aaron Shingler, James Davies and John Barclay adding experience to the back row.
Wales U20 hooker Ryan Elias and Wales scrum-half Gareth Davies have been released by their respective teams for the huge PRO12 clash.
"Connacht is a team sitting in the top six which is where we want to be," explained Pivac.
"Pat [Lam] has got some players in who've made a difference to the side and the local guys have all stepped up. They're a definite threat to the top 4 and top 6 scenario.
"We were disappointed when we went out there and lost 14-8 – it was a game we could have and should have won. We look forward to this game in what is a must win game for us."
Meanwhile, Irish international Kieran Marmion, who celebrated his 23rd birthday this week, has returned from camp to take his place at scrum-half for his 65th Connacht appearance. Jack Carty starts at fly-half for the 15th time this season.
Darragh Leader shifts from wing to full-back with Niyi Adeolokun and Matt Healy starting on the wings in a backline with an average age of just under 24.
In the centre, this season's top try scorer Danie Poolman is named to start outside Dave McSharry who recently committed two more years to the province.
Up front, the front row is boosted by the return of tighthead prop Nathan White who plays his first PRO12 game since October.
Jake Heenan makes his long awaited return since his injury in round 1 of the competition and starts in a back row with captain John Muldoon and number eight George Naoupu.
From the bench Eoghan Masterson and Tiernan O'Halloran are in line to make their season debut while it would be a first cap for outhalf Shane O'Leary if he was called upon.
Commenting on the team selection and the upcoming game Connacht head coach Pat Lam said: "We lost Eoin (McKeon) and Mils (Muliaina* to injury which was obviously a big blow especially on top of the loss of another back row in Willie (Faloon). But with these guys going down, it's good to welcome back Jake (Heenan) and Tiernan (O'Halloran) from long-term injuries.
"What we see with this team are the huge opportunities up for grabs for so many young players. The likes of Shane O'Leary, who has worked hard in training and for the Eagles, has his first match day involvement and we're delighted for him.
"This is a huge game for us against a well-coached and quality side in Scarlets. We know they are breathing right behind us and like us, they have top six aspirations.
"We haven't won on their soil since 2004 and we've never won at Parc y Scarlets. We've challenged ourselves to take it to another level for this block of four games, and it must start with a performance this Sunday."
Eoin McKeon sustained a fractured sternum and is expected to be out of action for four weeks. Mils Muliaina is also looking at up to four weeks on the sidelines with a hamstring tear.
Form: Scarlets have won just one of their last five contests in the PRO12 – 22-10 at home to Ospreys on 3 January. Scarlets are unbeaten in their last dozen fixtures at Parc y Scarlets in the PRO12 since Ospreys beat them there 10-6 on Boxing Day 2013. The Welshmen have yet to beat an Irish province in the PRO12 this season, however only one Irish side has been victorious at Parc y Scarlets since December 2012 – Leinster in the PRO12 on 6 September 2013. Connacht's only victory in their last four PRO12 encounters was 24-16 at home to Munster on New Year's Day. Connacht have not won away from home in the PRO12 since beating Benetton Treviso 9-6 at the Stadio Monigo in Round Six. The Irishmen have lost on their last three visits to Wales since beating Dragons 24-8 at Rodney Parade on 23 March 2014. Connacht beat Scarlets 14-8 in Galway in Round Nine and are going for a first ever PRO12 season's double over the Welshmen, however they have not beaten Scarlets on their own soil since a trip to Stradey Park on 9 October 2004.
Scarlets: 15 Jordan Williams, 14 Harry Robinson, 13 Regan King, 12 Hadleigh Parkes, 11 Michael Tagicakibau, 10 Steven Shingler, 9 Aled Davies, 8 John Barclay, 7 James Davies, 6 Aaron Shingler, 5 Johan Snyman, 4 Lewis Rawlins, 3 Peter Edwards, 2 Ken Owens (c), 1 Phil John.
Replacements: 16 Ryan Elias, 17 Ben Leung, 18 Jacobie Adriaanse, 19 George Earle, 20 Rob McCusker, 21 Gareth Davies, 22 Adam Warren, 23 Kristian Phillips
Connacht: 15 Darragh Leader, 14 Niyi Adeolokun, 13 Danie Poolman, 12 Dave McSharry, 11 Matt Healy, 10 Jack Carty, 9 Kieran Marmion, 8 George Naoupu, 7 Jake Heenan, 6 John Muldoon (c), 5 Aly Muldowney, 4 Quinn Roux, 3 Nathan White, 2 Tom McCartney, 1 Denis Buckley.
Replacements: 16 Dave Heffernan, 17 JP Cooney, 18 Rodney Ah You, 19 Ultan Dillane, 20 Eoghan Masterson, 21 Ian Porter, 22 Shane O'Leary, 23 Tiernan O'Halloran.
Date: Saturday, February 14
Venue: Parc y Scarlets
Kick-off: 12:45 GMT
Referee: Marius Mitrea (Italy)
Assistant Referees: Wayne Davies (Wales), Martyn Lewis (Wales)
TMO: Tim Hayes (Wales)