The former Kaizer Chiefs and Chippa United striker was released last week without kicking a ball for Baroka, shortly after being signed by the Limpopo-based outfit.
Baroka did the thing with Ivorian hitman Armand Gnanduille earlier in the transfer window.
"Ja, agreement between two parties huh!" Mammila tells KickOff.com.
"No, it was just a request from one party you know, and it was agreed. We can't disclose. That was our agreement not to disclose. This is something that happened last week."
Zulu has since reportedly linked up with National First Division side Maccabi FC.
Baroka also recently parted ways with forward Lucky Nguzana, who has joined Mbombela United in the NFD.
Asked if replacements will be sought, Mammila said: "No, we will not sign anyone. We are fine actually."