Head coach Nigel Davies has chosen to bring back the influential and experienced outside half a week before the Scarlets' opening European cup game against Brive at Parc y Scarlets on October 10th.
Jones was rested as a precaution at last weekend's high profile Welsh derby last weekend in Cardiff, to recover from a slight ankle injury.
Davies said: "Stephen 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 and does boss games particularly well."
"It's not only what he does on the field, it is what he contributes off the field as well and he is hugely respected by all the guys."
On preparations for Ulster, the Scarlets head coach said: "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."
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, a reward for Edwards's impressive form at semi-pro level for Llandovery.
Wales prop Rhys Thomas will also return to the side having missed the last two matches with stitches in a cut knee.
Captain Mark Jones said Friday's encounter will be about registering much needed points in the league and said his Wales team mate's return would boost the team: "I think the team on Friday night will be bolstered by having Stephen back in the squad, he does make a big difference.
"Ulster will be in a good frame of mind leading into this game and I think it's an important game for both teams as we approach Europe. The conditions up there are often difficult and the crowds are very hostile, but these environments are one of the reasons why you play rugby and I think some of the young guys will really relish that and hopefully we can get a good victory.
"Every Magners League game is important but this game becomes important from a points point of view, and icing on the cake will be that extra bit of confidence a win will give us going into the Heineken Cup."
Principality Stadium will host the UEFA Champions League Final in six weeks' time. WRU chairman Gareth Davies, Football Association of Wales chief executive Jonathan Ford and Ambassador Ian Rush joined young sports fans at the trophy arrival at the venue to celebrate the magnitude of the event on Saturday 3rd June (kick-off 19.45).
British and Irish Lions captain Sam Warburton is looking forward to bringing together players from Ireland, Scotland, England and Wales for the biggest challenge of their careers - a series against world champions, New Zealand.
For the fifth year running, Wales referee Nigel Owens will be in charge of proceedings at Judgement Day V at Principality Stadium. It promises to be 'extra special' for the Wales' favourite ref, as he will be making his 150th appearance in the league.
There will be no shortage of inside knowledge from Bowl Finalists Caerphilly and Amman United when they face each other on Sunday at National Finals Day. Caerphilly hooker Rhys Cleverly knows the Principality Stadium pitch better than most as a matchday groundsman, while Amman United can look to Wales' record try scorer Shane Williams for some helpful advice.
Two hundred and 40 teams competed in the inaugural Urdd WRU 7s held at Pencoed last week with Welsh internationals Steff Andrews and Jasmine Joyce impressed with the talent on display, as was Urdd chief executive, Sioned Hughes.
The countdown is on for Judgement Day V as tickets for the big day at Principality Stadium soar through the 50,000 mark. Players and coaches alike are bursting at the seams to play in the double header with Dragons coach Kingsley Jones claiming there is a 'real buzz' about the event.
WRU TV went behind the scenes when the four regions got together to test their skill set for the BBC's Scrum V Live rugby show, at the WRU National Centre of Excellene in the build up to Judgement Day V. Blues' Matthew Morgan was one of the stars of the show while the Dragons' Cory Hill proved a surprise package...the full set of results will be revealed on tv screens on matchday
Wales assistant coach Richie Pugh is confident his side can cause a few headaches in the Hong Kong Sevens this weekend. In a tough group, Wales kick off their campaign against New Zealand on Friday before playing Japan and Fiji, who are chasing their third consecutive Hong Kong title, on Saturday.
Bedwas had to overcome a stubborn Carmarthen Quins side before winning the Foster's Challenge Cup final in Bridgend with a 23-18 victory. Bedwas captain Nicky Griffiths pays tribute to his side who have claimed the club's first piece of silverware in the modern era.
Team coach Brett Davey is aiming to keep his unbeaten run in cup finals at Principality Stadium intact when his side take on Amman United in the WRU Bowl final, after he guided Caerphilly to a 20-14 win against Cilfynydd in the semi-finals.
Penallta are hoping to go one step further than last season when falling to Bedlinog in the WRU Plate Final. After a titanic struggle against Nant Conwy, they have given themselves a great chance, after a hard fought 18-13 semi-final victory.