The 30-year-old was placed on the transfer list as Usuthu looked to plan ahead for the new campaign, in what will be the first full season for coach Craig Rosslee after his appointment late last year.
Joining Kgatla in the unwanted line were goalkeeper Mbongeni Mzimela, defenders Phumlani Mhamha and Luyanda Hlongwa, and striker Nyiko Tshabangu.
Five other players - Ramson Zhuwawo, Tsweu Mokoro, Kagiso Senamela, Joseph Malongoane and Bongani Mbele - would not have their contracts renewed, the club said, when they expired at the end of next month. The deals of Sifiso Vilakazi and Makhosonke Bhengu had already been terminated.
“We had a serious chat with the directors and with the technical team, and clearly we’ve had to take some radical changes to plan ahead,” said AmaZulu general manager Peter O’Connor.
“It’s one of those unfortunate things for some of the players but we believe these changes are necessary and we’d like to wish the players well.”
The Durban club was also keen to loan out three of its young midfielders - Andile Khumalo, Nkanyiso Cele and Dumisani Zwane.
AmaZulu, who had a forgettable season in which they ended 12th in the Premiership, had already recruited their first signing of the off-season, drafting in former Santos defender Bongi Macala on a two-year contract.