Published Thursday, 08 December 2011
Brian McLaughlin has recalled Pienaar at scrumhalf in place of Paul Marshall, who drops to the replacements bench.
He is partnered at half-back with Ian Humphreys, and the backline remains otherwise unchanged.
McAllister is given an opportunity to start at loosehead prop, with Ireland international Tom Court named among the replacements.
Stefan Terblanche, who arrived in Belfast on Sunday, has gone straight into the matchday squad and the former South Africa international, who has the ability to cover fullback, wing and centre, will win his first cap for the Province if he takes the field.
Commenting on his scrumhalf selection, McLaughlin said: "Paul is a terrific player and has proved himself over the past few weeks.
But Ruan was the Magner's League Player of the Year last season so he deserves a chance.
His match time has been limited so it will be good for him to get some time on the pitch. We now have two quality scrumhalves."
Offering his reasons for selecting McAllister instead of Court in the front row, McLaughlin added, "It was important for Paddy McAllister's development to start in a match at this level.
"It means we have the option to bring a quality player like Tom on if we need to."
"We also have Stefan in the squad", The coach continued.
"He's a true professional and will add a great deal to the team in terms of his experience.
"He's an international player and has played for the Ospreys in Europe so he will be comfortable if he comes on."
Ulster team to face Aironi (Ravehill, Friday 9th December, KO 7:30pm)
Backs: A D'Arcy; A Trimble, D Cave, N Spence, C Gilroy; I Humphreys, R Pienaar;
Forwards: P McAllister, R Best, J Afoa, J Muller (capt), D Tuohy, S Ferris, C Henry, P Wannenburg;
Replacements: A Kyriacou, T Court, A Macklin, L Stevenson, R Diack, P Marshall, P Jackson, S Terblanche