The winger, who returned to the club from SuperSport United in August, was initially expected to be back in action next year after undergoing knee surgery.
However, Urban Warriors boss Muhsin Ertugral revealed Cale's injury, which he suspects was a pre-existing one, will take longer to heal than first anticipated.
"Franklin is out for the rest of the season," Ertugral said this afternoon.
"It's not that he got injured when he was training with the team but I think he came with the injury (from SuperSport) and it might take a while for him to get better."
Ertugral also confirmed that midfielder Ndumiso Vezi is likewise sidelined until the next campaign as he recovers from being knocked over by a car in May.
"Vezi is also out for the rest of the season, which is something very sad because, also, I think he's a bright player and to me it's a major blow," Ertugral concluded.