Dublin - The Springboks will put Ulster scrumhalf Ruan Pienaar through his paces in training this week before making a decision on both his availability for Saturday's Test with Ireland and the remainder of their northern hemisphere tour.
Pienaar is working his way back from a medial ligament injury picked up against New Zealand in Wellington in September and will test the knee in training over the next few days.
Springbok doctor Craig Roberts told reporters on Monday that Pienaar would struggle to make the Dublin match, 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.
"The biggest decision we have to make this week is around Ruan Pienaar," Roberts told reporters.
"We have assessed him and we're relatively happy with where he is, but we are going to have see when he is running on the field in training.
"At this stage it does not look like he will be available for this weekend, but we are hoping to have him ready for England.
"If he is not going to be ready for that then we may need to look at a replacement for the tour."
Pienaar, who is the only doubt, has played his club rugby at Ulster since 2010 and his experience in European conditions is seen as useful for the World Cup in England next year.
With first-choice scrumhalf Fourie du Preez also missing through injury, the Boks will almost certainly start with Francois Hougaard at scrumhalf on Saturday should Pienaar be ruled out, with inexperienced Cobus Reinach on the bench.
The Boks will play four Tests in their northern hemisphere tour on consecutive Saturdays.
After Ireland and England they take on Italy (November 22) and Wales (November 29).