Although Pienaar came through the tests without any problems, a final decision on his participation in the Outgoing Tour will be made on Tuesday.
"We would just like to see how he responds overnight, but at the moment it’s looking positive," said Springbok team doctor Craig Roberts.
Pienaar is working his way back from a medial ligament injury picked up against the All Blacks in Wellington in September.
Earlier it was reported that Roberts told reporters that Pienaar would struggle to make it in time for their Test against Ireland, and that if he was a doubt for the match with England at Twickenham a week later, the team would consider calling up a replacement.
With Fourie du Preez also missing through injury, Francois Hougaard will most likely be given the number 9 jersey on Saturday, with the only other scrumhalf in the squad, Cobus Reinach, to slot in on the bench.
The Boks will play four Tests in their northern hemisphere tour against Ireland (on Saturday), England (15 November), Italy (November 22) and Wales (November 29).