Sidelined for 12 weeks with a knee injury, Pienaar’s absence was sorely missed, particularly in the opening couple of games in Europe when Ulster crashed to two defeats and virtually ended their campaign.
The Bloemfontein-born scrum-half with 80 appearances for South Africa under his belt, is now in the vanguard to help Ulster finally grab a little bit of silverware in the shape of the Guinness Pro12 League title.
Pienaar is again in the mix partnering Ian Humphreys at half-back as head coach Neil Doak makes just two changes from the reverse against the Scarlets last week which stymied any hope of a European fight-back.
Doak has named Michael Allen on the left wing with Craig Gilroy rested and Andrew Warwick coming in at loose-head for Callum Black for the trip to face the Ospreys who are in second place but on the same 31 points as fourth-placed Ulster.
With the four teams at the top separated by just one point, Ulster hope they can spark a revival and grab some silverware that Pienaar is aiming for before he goes back home.
“I still believe we have a good thing going here,” says the 30-year-old Pienaar who turned down the advances of money-rich Toulon to stay with Ulster until the end of the 2017 season. “We’ve got a good team and as long as we can keep our key players, reduce the injuries, we always have a chance of being at the sharp end of things. I’ve always enjoyed my time here, my life in Belfast is good and the family have settled in.
We have guys who have given their all. I don’t want to leave them without seeing them winning a trophy they deserve,” said Pienaar who was obviously disappointed in Ulster going out of Europe.
“Those are the games you want to play,” he says. “It’s part of sport, you get disappointments like that and I’m sorry I wasn’t able to help the team.”
It’s always tough missing those big games. Originally they said the injury was going to be six or eight weeks and I might have had an outside chance of making Europe. It took a bit longer for me to get back playing again. So it was hugely disappointing.
Ospreys, meanwhile, have no injury worries.
OSPREYS: D Evans; H Dirksen, A Beck, J Matavesi, E Walker; D Biggar, R Webb; M Thomas, S Baldwin, D Arhip, R Bernardo, A Wyn Jones (Capt), J King, J Tipuric, T Ardron Replacements: S Parry, G Thomas, D Suter, D Lydiate, S Lewis, M Roberts, S Davies, A Bishop ULSTER: L Ludik; T Bowe, D Cave, L Marshall, M Allen; I Humphreys, R Pienaar; A Warwick, R Best (Capt), D Fitzpatrick; D Tuohy, F vd Merwe; R Diack, C Ross, R Wilson.
Replacements: R Herring, C Black, B Ross, A O’Connor, S Reidy, P Marshall, S Olding, P Nelson.
Referee: Neil Paterson (SRU).