Fourie had hoped to be ready for the start of the new campaign but told The Rugby Paper that his recovery is taking longer than first anticipated.
"The shoulder is going to take a little bit more time than expected," said Fourie.
"It's going to be a while longer before I am back.
"The shoulder gets really irritated when I do heavy weights. A scan showed the bone graft is only 55 percent healed so we're going to offload it for a bit and see if that makes a difference."
Fourie has been sidelined with the shoulder injury since February.