Pienaar sustained the injury while on international duty with South Africa in September.
He has been forced to sit out of the Springboks' autumn internationals, watching on as they were beaten by Ireland at the Aviva Stadium earlier this month.
However, Ulster's victory over previously unbeaten GUINNESS PRO12 leaders Ospreys last weekend lifted the 30-year-old's mood.
He is targeting a return to action with the Irish province for next month's European double against Scarlets, before Ulster once again lock horns with Ospreys in the league.
But first Neil Doak's side head to Thomond Park to face Munster on Friday night and Pienaar will be willing his teammates on from the treatment table.
"I think the rehab is going well," he told Rugby 365. "I would have liked to have been back playing now. I have started running, changing direction and that sort of thing.
"Hopefully I will be back in the next couple of weeks. I am really positive about being involved in the first week of December for that first Scarlets game.
"I'll train hard this week, do all the rehab and hopefully I will be back soon.
"The Ospreys performance was great. To get a win against a good Ospreys team was fantastic as was not giving them a point.
"I think everyone is looking forward to the game against Munster. It's a massive test, it's a derby and hopefully we can get a result down there."
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