Dublin - Ruan Pienaar has been ruled out of the Springboks' Northern Hemisphere tour because of a knee ligament injury and he will be replaced by Jano Vermaak. Pienaar picked up the injury in the Springboks’ Test against New Zealand in Wellington in September and has been out of action since then. "Ruan was re-assessed on Tuesday morning following the on-field fitness tests from Monday, and unfortunately he has developed some swelling and puffiness around the knee, indicating that he is not yet ready to partake in full training and playing in a match," said Springbok team doctor Craig Roberts. "He needs a few more weeks of rehabilitation before he’ll be ready to return to play and hence we’ve taken the decision to rule him out of the tour." Springbok coach Heyneke Meyer said he felt for Pienaar."We’ll miss his experience, especially when it comes to playing rugby in the Northern Hemisphere, but luckily Jano knows our structures and should not have a problem to slot back in,” said Meyer. “The decision to bring in Jano was because he is familiar with our structures and is also very experienced, especially since Cobus Reinach is still in his first season of Test rugby. "There are a number of good young scrumhalves in South Africa, but to bring someone in who has not yet trained with us in a pivotal position such as scrumhalf would’ve been a risk." Vermaak, who played in three Tests in 2013 and has been part of the squad for most of the previous two seasons, will join the Springbok squad in Dublin by Wednesday.