Spies, who played in his 50th Test against England in Port Elizabeth in June, injured his finger in the Vodacom Super Rugby Qualifier against the Crusaders last month.
According to Springbok team doctor Craig Roberts, initial X-rays did not reveal any significant abnormality.
“However, on review and further investigation, including a CT scan and assessment by a hand specialist in Cape Town, it was found that Pierre had a fracture into the joint,” said Roberts.
“Surgical correction is needed in order to prevent permanent damage. The usual rehabilitation time for these kinds of injuries is eight to 12 weeks.”
At this stage, Spies will not be replaced in the Springbok squad currently preparing for the opening Test of The Castle Rugby Championship, on Saturday at DHL Newlands, against Argentina.
“We have faith in the players in the squad and will consider the call-up of a possible replacement at a later stage,” said Springbok coach Heyneke Meyer.
“Losing Pierre is obviously a setback, because he is the most experienced member of our forward pack, but we will never take any risks with injured players. Injuries are part of the game and this now provides an opportunity for someone else to stake a claim.”
Spies joins four other Springbok loose forwards that are currently not available for selection. Schalk Burger, Juan Smith and Heinrich Brüssow are injured, while Ryan Kankowski is not available because of club commitments in Japan.
Furthermore another player that was in the selection frame, Duane Vermeulen, will only return to action for DHL Western Province in the Absa Currie Cup this weekend after a four-month layoff because of a knee injury.
Lock forward Eben Etzebeth took full part in training on Tuesday. The Springbok team for the first Test will be named on Wednesday.