Gcaba, 32, was training at Kings with hopes of earning a contract, but his age seemingly worked against him.
"Unfortunately we decided not to sign Gcaba," Dladla said.
"Even though we need defenders but the management thought he won't be a good addition for long-term, as we want to add young players to the squad."
Gcaba also had unsuccessful trials at Highlands Park and Black Leopards after ending a six-year tenure at Pirates on loan at Platinum Stars last term.
Kings, however, did hand deals to former Mali U-20 striker Mohamed Diallo and ex-Golden Arrows midfielder Kwanele Hlongwane in the January transfer window.
"We've signed a Mali striker Mohamed Diallo, as we want to fight against relegation in the National First Division."
Kings are in the drop zone with 18 points from as many matches - a point above bottom-placed Ubuntu Cape Town with 12 matches remaining.