The experienced player, who is a free agent, was released by the Urban Warriors at the end of the 2016/17 campaign.
Mokoena was signed by the Mother City side in August 2016 after impressing Roger De Sa on trial along with Mark Mayambela.
However, De Sa resigned as Ajax head coach two months later following a poor string of results and he was replaced by Dutch tactician Stanley Menzo.
"I had a fall-out at Ajax Cape Town. When Roger De Sa left, it became difficult," Mokoena told Power FM.
The attacker made only six appearances in the Premier Soccer League (PSL) without scoring for Ajax and he was released in June 2017.
"They said coach Stanley Menzo does not want to use me," he continued.
The Soweto-born player signed a two-year deal with the Urban Warriors, but he left after it was terminated.
"I could not even go on loan. The contract at Ajax ended at the end of last season," Mokoena added.
The 31-year-old winger, who has been clubless since leaving Ajax, joined PSL returnees Highlands Park on trial earlier this week.
"I am young. I cannot quit now. I am young. Well, Ajax paid for the remainder of the contract," he revealed.
"But it was difficult for me to move. But I decided to move elsewhere," he said.
Highlands mentor Owen Da Gama, who coached Mokoena at Pirates, recently indicated that he has been impressed by the experienced attacker.
"Owen Da Gama invited me at Highlands. I am enjoying myself. I worked with Owen at Pirates," he concluded.
Mokoena played his best football at Pirates where he worked with Da Gama between 2007 and 2008.
He left the Buccaneers for Mamelodi Sundowns in 2009.